diff --git a/.eslintrc.json b/.eslintrc.json
index 61e8895..41a5fdc 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -1,4 +1,9 @@
 {
+  "extends": [
+    "eslint:recommended",
+    "./package.json"
+  ],
+
   "env": {
     "browser": false,
     "es6": true,
@@ -6,6 +11,15 @@
     "mocha": true
   },
 
+  "parserOptions":{
+    "ecmaVersion": 9,
+    "sourceType": "module",
+    "ecmaFeatures": {
+      "modules": true,
+      "experimentalObjectRestSpread": true
+    }
+  },
+
   "globals": {
     "document": false,
     "navigator": false,
diff --git a/.gitignore b/.gitignore
index 4bf0a60..f969a2c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,7 @@
 # always ignore files
 *.DS_Store
 .idea
+.vscode
 *.sublime-*
 
 # test related, or directories generated by tests
diff --git a/.travis.yml b/.travis.yml
index 67decb2..1fd107d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,10 +5,7 @@ os:
 language: node_js
 node_js:
   - node
+  - '9'
   - '8'
   - '7'
   - '6'
-  - '5'
-  - '4'
-  - '0.12'
-  - '0.10'
diff --git a/.verb.md b/.verb.md
index 9a39e80..ecda709 100644
--- a/.verb.md
+++ b/.verb.md
@@ -10,9 +10,9 @@ Please see the [changelog](CHANGELOG.md) to learn about breaking changes that we
 Add the HTML in the following example to `example.html`, then add the following code to `example.js` and run `$ node example` (without the `$`):
 
 ```js
-var fs = require('fs');
-var matter = require('gray-matter');
-var str = fs.readFileSync('example.html', 'utf8');
+const fs = require('fs');
+const matter = require('gray-matter');
+const str = fs.readFileSync('example.html', 'utf8');
 console.log(matter(str));
 ```
 
@@ -72,10 +72,10 @@ Some libraries met most of the requirements, but _none met all of them_.
 * Have no problem with complex content, including **non-front-matter** fenced code blocks that contain examples of YAML front matter. Other parsers fail on this.
 * Support stringifying back to front-matter. This is useful for linting, updating properties, etc.
 * Allow custom delimiters, when it's necessary for avoiding delimiter collision. 
-* Should return an object with at least these three properties (for debugging):
+* Should return an object with at least these three properties:
   - `data`: the parsed YAML front matter, as a JSON object
   - `content`: the contents as a string, without the front matter
-  - `orig`: the "original" content
+  - `orig`: the "original" content (for debugging)
 
 </details>
 
@@ -85,7 +85,7 @@ Some libraries met most of the requirements, but _none met all of them_.
 Using Node's `require()` system:
 
 ```js
-var matter = require('gray-matter');
+const matter = require('gray-matter');
 ```
 
 Or with [typescript](https://www.typescriptlang.org)
@@ -126,6 +126,8 @@ gray-matter returns a `file` object with the following properties.
 - `file.data` **{Object}**: the object created by parsing front-matter
 - `file.content` **{String}**: the input string, with `matter` stripped
 - `file.excerpt` **{String}**: an excerpt, if [defined on the options](#optionsexcerpt)
+- `file.empty` **{String}**: when the front-matter is "empty" (either all whitespace, nothing at all, or just comments and no data), the original string is set on this property. See [#65](https://github.com/jonschlinkert/gray-matter/issues/65) for details regarding use case.
+- `file.isEmpty` **{Boolean}**: true if front-matter is empty.
 
 **Non-enumerable**
 
@@ -134,7 +136,7 @@ In addition, the following non-enumberable properties are added to the object to
 - `file.orig` **{Buffer}**: the original input string (or buffer)
 - `file.language` **{String}**: the front-matter language that was parsed. `yaml` is the default
 - `file.matter` **{String}**: the _raw_, un-parsed front-matter string
-- `file.stringify` **{Function}**: [stringify](#stringify) the file by converting `file.data` to a string in the given language, wrapping it in delimiters and appending it to `file.content`.
+- `file.stringify` **{Function}**: [stringify](#stringify) the file by converting `file.data` to a string in the given language, wrapping it in delimiters and prepending it to `file.content`.
 
 
 ## Run the examples
@@ -157,6 +159,8 @@ Then run any of the [examples](./examples) to see how gray-matter works:
 $ node examples/<example_name>
 ```
 
+**Links to examples**
+
 {%= examples() %} 
 
 
@@ -168,26 +172,60 @@ $ node examples/<example_name>
 
 ### options.excerpt
 
-**Type**: `Object`
+**Type**: `Boolean|Function`
 
 **Default**: `undefined`
 
 Extract an excerpt that directly follows front-matter, or is the first thing in the string if no front-matter exists.
 
+If set to `excerpt: true`, it will look for the frontmatter delimiter, `---` by default and grab everything leading up to it.
+
 **Example**
 
 ```js
-var str = '--\ntitle: Home\n---\nAn excerpt\n---\nOther stuff';
-console.log(matter(str, {excerpt: true}));
+const str = '---\nfoo: bar\n---\nThis is an excerpt.\n---\nThis is content';
+const file = matter(str, { excerpt: true });
+```
+
+Results in:
+
+```js
+{ 
+  content: 'This is an excerpt.\n---\nThis is content',
+  data: { foo: 'bar' },
+  excerpt: 'This is an excerpt.\n' 
+}
+```
+
+You can also set `excerpt` to a function. This function uses the 'file' and 'options' that were initially passed to gray-matter as parameters, so you can control how the excerpt is extracted from the content.
+
+**Example**
+
+```js
+// returns the first 4 lines of the contents
+function firstFourLines(file, options) {
+  file.excerpt = file.content.split('\n').slice(0, 4).join(' ');
+}
+
+const file =  matter([
+  '---',
+  'foo: bar',
+  '---',
+  'Only this',
+  'will be',
+  'in the',
+  'excerpt',
+  'but not this...'
+].join('\n'), {excerpt: firstFourLines});
 ```
 
 Results in:
 
 ```js
 { 
-  data: { title: 'Home'}, 
-  excerpt: '\nAn excerpt', 
-  content: '\nAn excerpt\n---\nOther stuff' 
+  content: 'Only this\nwill be\nin the\nexcerpt\nbut not this...',
+  data: { foo: 'bar' },
+  excerpt: 'Only this will be in the excerpt'
 }
 ```
 
@@ -242,13 +280,13 @@ Engines may either be an object with `parse` and (optionally) `stringify` method
 **Examples**
 
 ```js
-var toml = require('toml');
+const toml = require('toml');
 
 /**
  * defined as a function
  */
 
-var file = matter(str, {
+const file = matter(str, {
   engines: {
     toml: toml.parse.bind(toml),
   }
@@ -258,7 +296,7 @@ var file = matter(str, {
  * Or as an object
  */
 
-var file = matter(str, {
+const file = matter(str, {
   engines: {
     toml: {
       parse: toml.parse.bind(toml),
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5ced795..eebdf42 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,15 +1,24 @@
 # Release history
 
-## Unreleased
+## 4.0.0 - 2018-04-01
+
+### Breaking changes
+
+- Now requires node v4 or higher. 
+
 
 ## 3.0.0 - 2017-06-30
+
 ### Breaking changes
-* `toml`, `coffee` and `cson` are no longer supported by default. Please see [`options.engines`](README.md#optionsengines) and the [examples](./examples) to learn how to add engines.
+
+- `toml`, `coffee` and `cson` are no longer supported by default. Please see [`options.engines`](README.md#optionsengines) and the [examples](./examples) to learn how to add engines.
 
 ### Added
-* Support for [excerpts](README.md#optionsexcerpt).
-* The returned object now has non-enumerable `matter` and `stringify` properties.
+
+- Support for [excerpts](README.md#optionsexcerpt).
+- The returned object now has non-enumerable `matter` and `stringify` properties.
 
 ### Changed
-* Refactored engines (parsers), so that it's easier to add parsers and stringifiers.
-* `options.parsers` was renamed to [`options.engines`](README.md#optionsengines)
+
+- Refactored engines (parsers), so that it's easier to add parsers and stringifiers.
+- `options.parsers` was renamed to [`options.engines`](README.md#optionsengines)
diff --git a/LICENSE b/LICENSE
index 3f2eca1..d32ab44 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,6 +1,6 @@
 The MIT License (MIT)
 
-Copyright (c) 2014-2017, Jon Schlinkert.
+Copyright (c) 2014-2018, Jon Schlinkert.
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/README.md b/README.md
index 15c32fc..d5d1e0a 100644
--- a/README.md
+++ b/README.md
@@ -24,9 +24,9 @@ Please see the [changelog](CHANGELOG.md) to learn about breaking changes that we
 Add the HTML in the following example to `example.html`, then add the following code to `example.js` and run `$ node example` (without the `$`):
 
 ```js
-var fs = require('fs');
-var matter = require('gray-matter');
-var str = fs.readFileSync('example.html', 'utf8');
+const fs = require('fs');
+const matter = require('gray-matter');
+const str = fs.readFileSync('example.html', 'utf8');
 console.log(matter(str));
 ```
 
@@ -85,10 +85,10 @@ Some libraries met most of the requirements, but _none met all of them_.
 * Have no problem with complex content, including **non-front-matter** fenced code blocks that contain examples of YAML front matter. Other parsers fail on this.
 * Support stringifying back to front-matter. This is useful for linting, updating properties, etc.
 * Allow custom delimiters, when it's necessary for avoiding delimiter collision.
-* Should return an object with at least these three properties (for debugging):
+* Should return an object with at least these three properties:
   - `data`: the parsed YAML front matter, as a JSON object
   - `content`: the contents as a string, without the front matter
-  - `orig`: the "original" content
+  - `orig`: the "original" content (for debugging)
 
 </details>
 
@@ -97,7 +97,7 @@ Some libraries met most of the requirements, but _none met all of them_.
 Using Node's `require()` system:
 
 ```js
-var matter = require('gray-matter');
+const matter = require('gray-matter');
 ```
 
 Or with [typescript](https://www.typescriptlang.org)
@@ -138,6 +138,8 @@ gray-matter returns a `file` object with the following properties.
 * `file.data` **{Object}**: the object created by parsing front-matter
 * `file.content` **{String}**: the input string, with `matter` stripped
 * `file.excerpt` **{String}**: an excerpt, if [defined on the options](#optionsexcerpt)
+* `file.empty` **{String}**: when the front-matter is "empty" (either all whitespace, nothing at all, or just comments and no data), the original string is set on this property. See [#65](https://github.com/jonschlinkert/gray-matter/issues/65) for details regarding use case.
+* `file.isEmpty` **{Boolean}**: true if front-matter is empty.
 
 **Non-enumerable**
 
@@ -146,7 +148,7 @@ In addition, the following non-enumberable properties are added to the object to
 * `file.orig` **{Buffer}**: the original input string (or buffer)
 * `file.language` **{String}**: the front-matter language that was parsed. `yaml` is the default
 * `file.matter` **{String}**: the _raw_, un-parsed front-matter string
-* `file.stringify` **{Function}**: [stringify](#stringify) the file by converting `file.data` to a string in the given language, wrapping it in delimiters and appending it to `file.content`.
+* `file.stringify` **{Function}**: [stringify](#stringify) the file by converting `file.data` to a string in the given language, wrapping it in delimiters and prepending it to `file.content`.
 
 ## Run the examples
 
@@ -168,6 +170,8 @@ Then run any of the [examples](./examples) to see how gray-matter works:
 $ node examples/<example_name>
 ```
 
+**Links to examples**
+
 * [coffee](examples/coffee.js)
 * [excerpt-separator](examples/excerpt-separator.js)
 * [excerpt-stringify](examples/excerpt-stringify.js)
@@ -175,13 +179,16 @@ $ node examples/<example_name>
 * [javascript](examples/javascript.js)
 * [json-stringify](examples/json-stringify.js)
 * [json](examples/json.js)
+* [restore-empty](examples/restore-empty.js)
+* [sections-excerpt](examples/sections-excerpt.js)
+* [sections](examples/sections.js)
 * [toml](examples/toml.js)
 * [yaml-stringify](examples/yaml-stringify.js)
 * [yaml](examples/yaml.js)
 
 ## API
 
-### [matter](index.js#L30)
+### [matter](index.js#L29)
 
 Takes a string or object with `content` property, extracts and parses front-matter from the string, then returns an object with `data`, `content` and other [useful properties](#returned-object).
 
@@ -194,12 +201,12 @@ Takes a string or object with `content` property, extracts and parses front-matt
 **Example**
 
 ```js
-var matter = require('gray-matter');
+const matter = require('gray-matter');
 console.log(matter('---\ntitle: Home\n---\nOther stuff'));
 //=> { data: { title: 'Home'}, content: 'Other stuff' }
 ```
 
-### [.stringify](index.js#L140)
+### [.stringify](index.js#L160)
 
 Stringify an object to YAML or the specified language, and append it to the given string. By default, only YAML and JSON can be stringified. See the [engines](#engines) section to learn how to stringify other languages.
 
@@ -221,7 +228,7 @@ console.log(matter.stringify('foo bar baz', {title: 'Home'}));
 // foo bar baz
 ```
 
-### [.read](index.js#L160)
+### [.read](index.js#L178)
 
 Synchronously read a file from the file system and parse front matter. Returns the same object as the [main function](#matter).
 
@@ -234,10 +241,10 @@ Synchronously read a file from the file system and parse front matter. Returns t
 **Example**
 
 ```js
-var file = matter.read('./content/blog-post.md');
+const file = matter.read('./content/blog-post.md');
 ```
 
-### [.test](index.js#L175)
+### [.test](index.js#L193)
 
 Returns true if the given `string` has front matter.
 
@@ -251,26 +258,60 @@ Returns true if the given `string` has front matter.
 
 ### options.excerpt
 
-**Type**: `Object`
+**Type**: `Boolean|Function`
 
 **Default**: `undefined`
 
 Extract an excerpt that directly follows front-matter, or is the first thing in the string if no front-matter exists.
 
+If set to `excerpt: true`, it will look for the frontmatter delimiter, `---` by default and grab everything leading up to it.
+
 **Example**
 
 ```js
-var str = '--\ntitle: Home\n---\nAn excerpt\n---\nOther stuff';
-console.log(matter(str, {excerpt: true}));
+const str = '---\nfoo: bar\n---\nThis is an excerpt.\n---\nThis is content';
+const file = matter(str, { excerpt: true });
+```
+
+Results in:
+
+```js
+{ 
+  content: 'This is an excerpt.\n---\nThis is content',
+  data: { foo: 'bar' },
+  excerpt: 'This is an excerpt.\n' 
+}
+```
+
+You can also set `excerpt` to a function. This function uses the 'file' and 'options' that were initially passed to gray-matter as parameters, so you can control how the excerpt is extracted from the content.
+
+**Example**
+
+```js
+// returns the first 4 lines of the contents
+function firstFourLines(file, options) {
+  file.excerpt = file.content.split('\n').slice(0, 4).join(' ');
+}
+
+const file =  matter([
+  '---',
+  'foo: bar',
+  '---',
+  'Only this',
+  'will be',
+  'in the',
+  'excerpt',
+  'but not this...'
+].join('\n'), {excerpt: firstFourLines});
 ```
 
 Results in:
 
 ```js
 { 
-  data: { title: 'Home'}, 
-  excerpt: '\nAn excerpt', 
-  content: '\nAn excerpt\n---\nOther stuff' 
+  content: 'Only this\nwill be\nin the\nexcerpt\nbut not this...',
+  data: { foo: 'bar' },
+  excerpt: 'Only this will be in the excerpt'
 }
 ```
 
@@ -324,13 +365,13 @@ Engines may either be an object with `parse` and (optionally) `stringify` method
 **Examples**
 
 ```js
-var toml = require('toml');
+const toml = require('toml');
 
 /**
  * defined as a function
  */
 
-var file = matter(str, {
+const file = matter(str, {
   engines: {
     toml: toml.parse.bind(toml),
   }
@@ -340,7 +381,7 @@ var file = matter(str, {
  * Or as an object
  */
 
-var file = matter(str, {
+const file = matter(str, {
   engines: {
     toml: {
       parse: toml.parse.bind(toml),
@@ -486,34 +527,39 @@ You might also be interested in these projects:
 * [assemble](https://www.npmjs.com/package/assemble): Get the rocks out of your socks! Assemble makes you fast at creating web projects… [more](https://github.com/assemble/assemble) | [homepage](https://github.com/assemble/assemble "Get the rocks out of your socks! Assemble makes you fast at creating web projects. Assemble is used by thousands of projects for rapid prototyping, creating themes, scaffolds, boilerplates, e-books, UI components, API documentation, blogs, building websit")
 * [metalsmith](https://www.npmjs.com/package/metalsmith): An extremely simple, pluggable static site generator. | [homepage](https://github.com/segmentio/metalsmith#readme "An extremely simple, pluggable static site generator.")
 * [verb](https://www.npmjs.com/package/verb): Documentation generator for GitHub projects. Verb is extremely powerful, easy to use, and is used… [more](https://github.com/verbose/verb) | [homepage](https://github.com/verbose/verb "Documentation generator for GitHub projects. Verb is extremely powerful, easy to use, and is used on hundreds of projects of all sizes to generate everything from API docs to readmes.")
+* [gray-matter-loader](https://github.com/atlassian/gray-matter-loader): A webpack loader for gray-matter. [homepage](https://github.com/atlassian/gray-matter-loader#gray-matter-loader)
 
 ### Contributors
 
 | **Commits** | **Contributor** | 
 | --- | --- |
-| 163 | [jonschlinkert](https://github.com/jonschlinkert) |
+| 174 | [jonschlinkert](https://github.com/jonschlinkert) |
 | 7 | [RobLoach](https://github.com/RobLoach) |
 | 5 | [heymind](https://github.com/heymind) |
-| 2 | [doowb](https://github.com/doowb) |
+| 4 | [doowb](https://github.com/doowb) |
+| 3 | [aljopro](https://github.com/aljopro) |
+| 2 | [reccanti](https://github.com/reccanti) |
 | 2 | [onokumus](https://github.com/onokumus) |
 | 2 | [moozzyk](https://github.com/moozzyk) |
 | 1 | [Ajedi32](https://github.com/Ajedi32) |
 | 1 | [caesar](https://github.com/caesar) |
 | 1 | [ianstormtaylor](https://github.com/ianstormtaylor) |
+| 1 | [qm3ster](https://github.com/qm3ster) |
 | 1 | [zachwhaley](https://github.com/zachwhaley) |
 
 ### Author
 
 **Jon Schlinkert**
 
-* [github/jonschlinkert](https://github.com/jonschlinkert)
-* [twitter/jonschlinkert](https://twitter.com/jonschlinkert)
+* [LinkedIn Profile](https://linkedin.com/in/jonschlinkert)
+* [GitHub Profile](https://github.com/jonschlinkert)
+* [Twitter Profile](https://twitter.com/jonschlinkert)
 
 ### License
 
-Copyright © 2017, [Jon Schlinkert](https://github.com/jonschlinkert).
+Copyright © 2018, [Jon Schlinkert](https://github.com/jonschlinkert).
 Released under the [MIT License](LICENSE).
 
 ***
 
-_This file was generated by [verb-generate-readme](https://github.com/verbose/verb-generate-readme), v0.6.0, on October 19, 2017._
\ No newline at end of file
+_This file was generated by [verb-generate-readme](https://github.com/verbose/verb-generate-readme), v0.6.0, on April 01, 2018._
\ No newline at end of file
diff --git a/bower.json b/bower.json
index 6c0bea2..e72652a 100644
--- a/bower.json
+++ b/bower.json
@@ -1,7 +1,7 @@
 {
   "name": "gray-matter",
   "description": "Parse front-matter from a string or file. Fast, reliable and easy to use. Parses YAML front matter by default, but also has support for YAML, JSON, TOML or Coffee Front-Matter, with options to set custom delimiters. Used by metalsmith, assemble, verb and many other projects.",
-  "version": "3.0.5",
+  "version": "3.1.1",
   "homepage": "https://github.com/jonschlinkert/gray-matter",
   "authors": [
     "Jon Schlinkert (https://github.com/jonschlinkert)"
@@ -32,27 +32,25 @@
     "index.js"
   ],
   "dependencies": {
-    "js-yaml": "^3.8.1",
-    "kind-of": "^5.0.0",
+    "define-property": "^2.0.2",
+    "js-yaml": "^3.11.0",
+    "kind-of": "^6.0.2",
+    "section-matter": "^1.0.0",
     "strip-bom-string": "^1.0.0"
   },
   "devDependencies": {
-    "ansi-bold": "^0.1.1",
-    "ansi-gray": "^0.1.1",
-    "ansi-magenta": "^0.1.1",
-    "benchmarked": "^0.2.5",
-    "coffee-script": "^1.12.6",
+    "ansi-green": "^0.1.1",
+    "benchmarked": "^2.0.0",
+    "coffeescript": "^2.2.3",
     "delimiter-regex": "^2.0.0",
-    "extend-shallow": "^2.0.1",
-    "for-own": "^0.1.4",
-    "front-matter": "^2.1.2",
-    "gulp-format-md": "^0.1.12",
-    "matched": "^1.0.2",
+    "extend-shallow": "^3.0.2",
+    "front-matter": "^2.3.0",
+    "gulp-format-md": "^1.0.0",
     "minimist": "^1.2.0",
-    "mocha": "^3.2.0",
-    "sort-object": "^3.0.2",
-    "toml": "^2.3.2",
-    "vinyl": "^2.0.2"
+    "mocha": "^3.5.3",
+    "toml": "^2.3.3",
+    "vinyl": "^2.1.0",
+    "write": "^1.0.3"
   },
   "keywords": [
     "assemble",
@@ -106,5 +104,13 @@
       }
     }
   },
-  "types": "gray-matter.d.ts"
+  "types": "gray-matter.d.ts",
+  "browser": {
+    "fs": false
+  },
+  "eslintConfig": {
+    "rules": {
+      "no-console": 0
+    }
+  }
 }
\ No newline at end of file
diff --git a/examples/cache.js b/examples/cache.js
deleted file mode 100644
index 7df47f5..0000000
--- a/examples/cache.js
+++ /dev/null
@@ -1,20 +0,0 @@
-// https://github.com/jonschlinkert/gray-matter/issues/43
-var frontMatter = require('gray-matter');
-
-var docs = [
-  {
-    id: 1,
-    content: ''
-  },
-  {
-    id: 2,
-    content: ''
-  }
-];
-
-var parsedDocs = docs.map(doc => {
-  var output = frontMatter(doc.content);
-  Object.assign(output, { id: doc.id });
-  return output;
-}).map(({ id }) => id);
-console.log(parsedDocs);
diff --git a/examples/coffee.js b/examples/coffee.js
index 57d49d7..0934114 100644
--- a/examples/coffee.js
+++ b/examples/coffee.js
@@ -1,10 +1,11 @@
-var path = require('path');
-var matter = require('..');
-var coffee = require('coffee-script');
-var magenta = require('ansi-magenta');
+const path = require('path');
+const matter = require('..');
+const coffee = require('coffeescript');
+const green = require('ansi-green');
+const fixture = path.join.bind(path, __dirname, 'fixtures');
+let file;
 
-var fixture = path.join.bind(path, __dirname, 'fixtures');
-var engines = {
+const engines = {
   coffee: {
     parse: function(str, options) {
       /* eslint no-eval: 0 */
@@ -13,13 +14,13 @@ var engines = {
   }
 };
 
-console.log(magenta('/* coffescript (detected after first delimiter) */'));
-var file = matter.read(fixture('coffee-auto.md'), {engines: engines});
+console.log(green('/* coffescript (detected after first delimiter in front-matter) */'));
+file = matter.read(fixture('coffee-auto.md'), {engines: engines});
 console.log(file);
 console.log();
 
-console.log(magenta('/* coffescript (defined on options) */'));
-var file = matter.read(fixture('coffee.md'), {
+console.log(green('/* coffescript (defined on options) */'));
+file = matter.read(fixture('coffee.md'), {
   language: 'coffee',
   engines: engines
 });
diff --git a/examples/excerpt-separator.js b/examples/excerpt-separator.js
index 91006b3..f68d30f 100644
--- a/examples/excerpt-separator.js
+++ b/examples/excerpt-separator.js
@@ -1,10 +1,8 @@
-var path = require('path');
-var matter = require('..');
-var fixture = path.join.bind(path, __dirname, 'fixtures');
-var magenta = require('ansi-magenta');
+const matter = require('..');
+const green = require('ansi-green');
 
-console.log(magenta('/* excerpt with custom separator */'));
-var file = matter([
+console.log(green('/* excerpt with custom separator */'));
+const file = matter([
   '---',
   'foo: bar',
   '---',
diff --git a/examples/excerpt-stringify.js b/examples/excerpt-stringify.js
index e5cf294..c1c9e55 100644
--- a/examples/excerpt-stringify.js
+++ b/examples/excerpt-stringify.js
@@ -1,9 +1,7 @@
-var path = require('path');
-var matter = require('..');
-var fixture = path.join.bind(path, __dirname, 'fixtures');
-var magenta = require('ansi-magenta');
+const matter = require('..');
+const green = require('ansi-green');
 
-var file = matter([
+const file = matter([
   '---',
   'foo: bar',
   '---',
@@ -12,9 +10,9 @@ var file = matter([
   'This is content'
 ].join('\n'), {excerpt_separator: '<!-- sep -->'});
 
-console.log(magenta('/* file object, with excerpt */'));
+console.log(green('/* file object, with excerpt */'));
 console.log(file);
 
 console.log();
-console.log(magenta('/* stringified, with excerpt */'));
+console.log(green('/* stringified, with excerpt */'));
 console.log(file.stringify());
diff --git a/examples/excerpt.js b/examples/excerpt.js
index 8918a52..77320aa 100644
--- a/examples/excerpt.js
+++ b/examples/excerpt.js
@@ -1,9 +1,8 @@
-var path = require('path');
-var matter = require('..');
-var fixture = path.join.bind(path, __dirname, 'fixtures');
-var magenta = require('ansi-magenta');
+const matter = require('..');
+const green = require('ansi-green');
 
-var file = matter([
+// excerpt as a boolean
+const file1 = matter([
   '---',
   'foo: bar',
   '---',
@@ -12,5 +11,26 @@ var file = matter([
   'This is content'
 ].join('\n'), {excerpt: true});
 
-console.log(magenta('/* excerpt */'));
-console.log(file);
+console.log(green('/* excerpt: true */'));
+console.log(file1);
+
+// excerpt as a function
+
+// returns the first 4 lines of the contents
+function firstFourLines(file, options) {
+  file.excerpt = file.content.split('\n').slice(0, 4).join(' ');
+}
+
+const file2 = matter([
+  '---',
+  'foo: bar',
+  '---',
+  'Only this',
+  'will be',
+  'in the',
+  'excerpt',
+  'but not this...'
+].join('\n'), { excerpt: firstFourLines });
+
+console.log(green('/* excerpt: function(file, options) { ... } */'));
+console.log(file2);
diff --git a/examples/fixtures/sections-excerpt.md b/examples/fixtures/sections-excerpt.md
new file mode 100644
index 0000000..9cfec28
--- /dev/null
+++ b/examples/fixtures/sections-excerpt.md
@@ -0,0 +1,32 @@
+---yaml
+title: I'm front matter
+---
+
+This is an excerpt.
+---
+
+---aaa
+title: First section
+---
+
+Section one.
+
+---bbb
+title: Second section
+---
+
+Part 1.
+
+---
+
+Part 2.
+
+---
+
+Part 3.
+
+---ccc
+title: Third section
+---
+
+Section three.
diff --git a/examples/fixtures/sections.md b/examples/fixtures/sections.md
new file mode 100644
index 0000000..361b6ec
--- /dev/null
+++ b/examples/fixtures/sections.md
@@ -0,0 +1,31 @@
+---yaml
+title: I'm front matter
+---
+
+This page has front matter that should be parsed before the sections.
+
+---aaa
+title: First section
+---
+
+Section one.
+
+---bbb
+title: Second section
+---
+
+Part 1.
+
+---
+
+Part 2.
+
+---
+
+Part 3.
+
+---ccc
+title: Third section
+---
+
+Section three.
diff --git a/examples/helper.js b/examples/helper.js
index ab1fd3d..b4ea5eb 100644
--- a/examples/helper.js
+++ b/examples/helper.js
@@ -3,16 +3,16 @@
  * the list of links to examples in the readme.
  */
 
-var fs = require('fs');
-var path = require('path');
+const fs = require('fs');
+const path = require('path');
 
 module.exports = function() {
-  var files = fs.readdirSync(__dirname);
-  var links = [];
-  for (var i = 0; i < files.length; i++) {
-    var name = files[i];
-    var ext = path.extname(name);
-    var stem = path.basename(name, ext);
+  const files = fs.readdirSync(__dirname);
+  const links = [];
+  for (let i = 0; i < files.length; i++) {
+    const name = files[i];
+    const ext = path.extname(name);
+    const stem = path.basename(name, ext);
     if (stem !== 'helper' && ext === '.js') {
       links.push('- [' + stem + '](examples/' + name + ')');
     }
diff --git a/examples/javascript.js b/examples/javascript.js
index 789244e..ae25c5d 100644
--- a/examples/javascript.js
+++ b/examples/javascript.js
@@ -1,8 +1,7 @@
-var path = require('path');
-var matter = require('..');
-var magenta = require('ansi-magenta');
+const matter = require('..');
+const green = require('ansi-green');
 
-var file = matter([
+const file = matter([
   '---js',
   '{',
   '  reverse: function(str) {',
@@ -13,10 +12,10 @@ var file = matter([
   'This is content'
 ].join('\n'));
 
-console.log(magenta('/* javascript front-matter */'));
+console.log(green('/* javascript front-matter */'));
 console.log(file);
 
 console.log();
-console.log(magenta('/* example after calling a function from front-matter */'));
+console.log(green('/* example after calling a function from front-matter */'));
 file.data.baz = file.data.reverse('x,y,z');
 console.log(file);
diff --git a/examples/json-stringify.js b/examples/json-stringify.js
index f0c29fb..2675aa1 100644
--- a/examples/json-stringify.js
+++ b/examples/json-stringify.js
@@ -1,9 +1,7 @@
-var path = require('path');
-var matter = require('..');
-var magenta = require('ansi-magenta');
-var fixture = path.join.bind(path, __dirname, 'fixtures');
+const matter = require('..');
+const green = require('ansi-green');
 
-var file = matter([
+const file1 = matter([
   '---json',
   '{',
   '  "name": "gray-matter"',
@@ -12,15 +10,15 @@ var file = matter([
   'This is content'
 ].join('\n'));
 
-console.log(magenta('/* stringified to YAML, from JSON front-matter */'));
-console.log(file.stringify({}, {language: 'yaml'}));
+console.log(green('/* stringified to YAML, from JSON front-matter */'));
+console.log(file1.stringify({}, {language: 'yaml'}));
 
-var file = matter([
+const file2 = matter([
   '---',
   'title: Home',
   '---',
   'This is content'
 ].join('\n'));
 
-console.log(magenta('/* stringified JSON, from YAML front-matter */'));
-console.log(file.stringify({}, {language: 'json', spaces: 2}));
+console.log(green('/* stringified JSON, from YAML front-matter */'));
+console.log(file2.stringify({}, {language: 'json', spaces: 2}));
diff --git a/examples/json.js b/examples/json.js
index 2e54be9..468669a 100644
--- a/examples/json.js
+++ b/examples/json.js
@@ -1,8 +1,6 @@
-var path = require('path');
-var matter = require('..');
-var magenta = require('ansi-magenta');
+const matter = require('..');
 
-var file = matter([
+const file1 = matter([
   '---json',
   '{',
   '  "name": "gray-matter"',
@@ -10,9 +8,9 @@ var file = matter([
   '---',
   'This is content'
 ].join('\n'));
-console.log(file);
+console.log(file1);
 
-var file = matter([
+const file2 = matter([
   '---json',
   '{',
   '  "name": "gray-matter"',
@@ -20,4 +18,4 @@ var file = matter([
   '---',
   'This is content'
 ].join('\n'));
-console.log(file);
+console.log(file2);
diff --git a/examples/restore-empty.js b/examples/restore-empty.js
new file mode 100644
index 0000000..d0187cc
--- /dev/null
+++ b/examples/restore-empty.js
@@ -0,0 +1,16 @@
+const matter = require('..');
+
+/**
+ * Parse YAML front-matter
+ */
+
+const str = `---
+---
+This is content`;
+const file = matter(str);
+
+console.log(file);
+if (file.isEmpty) {
+  file.content = str;
+}
+console.log(file);
diff --git a/examples/sections-excerpt.js b/examples/sections-excerpt.js
new file mode 100644
index 0000000..c870234
--- /dev/null
+++ b/examples/sections-excerpt.js
@@ -0,0 +1,9 @@
+'use strict';
+
+const fs = require('fs');
+const path = require('path');
+const matter = require('..');
+const str = fs.readFileSync(path.join(__dirname, 'fixtures', 'sections-excerpt.md'));
+
+const res = matter(str, { excerpt: true, sections: true });
+console.log(JSON.stringify(res, null, 2));
diff --git a/examples/sections.js b/examples/sections.js
new file mode 100644
index 0000000..bc6a6f3
--- /dev/null
+++ b/examples/sections.js
@@ -0,0 +1,18 @@
+'use strict';
+
+const fs = require('fs');
+const path = require('path');
+const yaml = require('js-yaml');
+const matter = require('..');
+const str = fs.readFileSync(path.join(__dirname, 'fixtures', 'sections.md'));
+
+const file = matter(str, {
+  section: function(section, file) {
+    if (typeof section.data === 'string' && section.data.trim() !== '') {
+      section.data = yaml.safeLoad(section.data);
+    }
+    section.content = section.content.trim() + '\n';
+  }
+});
+
+console.log(JSON.stringify(file, null, 2));
diff --git a/examples/toml.js b/examples/toml.js
index 55eaac8..3be613c 100644
--- a/examples/toml.js
+++ b/examples/toml.js
@@ -1,21 +1,20 @@
-var path = require('path');
-var matter = require('..');
-var toml = require('toml');
-var magenta = require('ansi-magenta');
-var fixture = path.join.bind(path, __dirname, 'fixtures');
+const matter = require('..');
+const toml = require('toml');
 
 /**
  * Parse TOML front-matter
  */
 
-var file = matter([
+const str = [
   '---toml',
   'title = "TOML"',
   'description = "Front matter"',
   'categories = "front matter toml"',
   '---',
   'This is content'
-].join('\n'), {
+].join('\n');
+
+const file = matter(str, {
   engines: {
     toml: toml.parse.bind(toml)
   }
diff --git a/examples/yaml-stringify.js b/examples/yaml-stringify.js
index 7d6bf86..508ed06 100644
--- a/examples/yaml-stringify.js
+++ b/examples/yaml-stringify.js
@@ -1,25 +1,22 @@
-var path = require('path');
-var matter = require('..');
-var magenta = require('ansi-magenta');
-var fixture = path.join.bind(path, __dirname, 'fixtures');
+const matter = require('..');
 
 /**
  * Stringify back to YAML
  */
 
-var file = matter([
+const file = matter([
   '---',
   'foo: bar',
   '---',
   'This is content'
 ].join('\n'));
 
-var str = file.stringify();
-console.log(str);
+const str1 = file.stringify();
+console.log(str1);
 
 /**
  * custom data
  */
 
-var str = file.stringify({baz: ['one', 'two', 'three']});
-console.log(str);
+const str2 = file.stringify({baz: ['one', 'two', 'three']});
+console.log(str2);
diff --git a/examples/yaml.js b/examples/yaml.js
index 99ef601..cce4020 100644
--- a/examples/yaml.js
+++ b/examples/yaml.js
@@ -1,13 +1,10 @@
-var path = require('path');
-var matter = require('..');
-var magenta = require('ansi-magenta');
-var fixture = path.join.bind(path, __dirname, 'fixtures');
+const matter = require('..');
 
 /**
  * Parse YAML front-matter
  */
 
-var file = matter([
+const file = matter([
   '---',
   'foo: bar',
   '---',
diff --git a/gray-matter.d.ts b/gray-matter.d.ts
index 76f8e04..dec9c09 100644
--- a/gray-matter.d.ts
+++ b/gray-matter.d.ts
@@ -1,15 +1,114 @@
-declare function matter(str: string, options?: matter.GrayMatterOption): any
+/**
+ * Takes a string or object with `content` property, extracts
+ * and parses front-matter from the string, then returns an object
+ * with `data`, `content` and other [useful properties](#returned-object).
+ *
+ * ```js
+ * var matter = require('gray-matter');
+ * console.log(matter('---\ntitle: Home\n---\nOther stuff'));
+ * //=> { data: { title: 'Home'}, content: 'Other stuff' }
+ * ```
+ * @param {Object|String} `input` String, or object with `content` string
+ * @param {Object} `options`
+ * @return {Object}
+ * @api public
+ */
+declare function matter<
+  I extends matter.Input,
+  O extends matter.GrayMatterOption<I, O>
+>(input: I | { content: I }, options?: O): matter.GrayMatterFile<I>
 
 declare namespace matter {
-  interface GrayMatterOption {
-    parser?: () => void;
-    eval?: boolean;
-    lang?: string;
-    delims?: string | string[];
+  type Input = string | Buffer
+  interface GrayMatterOption<
+    I extends Input,
+    O extends GrayMatterOption<I, O>
+  > {
+    parser?: () => void
+    eval?: boolean
+    excerpt?: boolean | ((input: I, options: O) => string)
+    excerpt_separator?: string
+    engines?: {
+      [index: string]:
+        | ((input: string) => object)
+        | { parse: (input: string) => object; stringify?: (data: object) => string }
+    }
+    language?: string
+    delimiters?: string | [string, string]
   }
-  export function read(fp: string, options?: GrayMatterOption): any;
-  export function stringify(str: string, data: object, options?: GrayMatterOption): string;
-  export function test(str: string, options?: GrayMatterOption): string;
+  interface GrayMatterFile<I extends Input> {
+    data: { [key: string]: any }
+    content: string
+    excerpt?: string
+    orig: Buffer | I
+    language: string
+    matter: string
+    stringify(lang: string): string
+  }
+  
+  /**
+   * Stringify an object to YAML or the specified language, and
+   * append it to the given string. By default, only YAML and JSON
+   * can be stringified. See the [engines](#engines) section to learn
+   * how to stringify other languages.
+   *
+   * ```js
+   * console.log(matter.stringify('foo bar baz', {title: 'Home'}));
+   * // results in:
+   * // ---
+   * // title: Home
+   * // ---
+   * // foo bar baz
+   * ```
+   * @param {String|Object} `file` The content string to append to stringified front-matter, or a file object with `file.content` string.
+   * @param {Object} `data` Front matter to stringify.
+   * @param {Object} `options` [Options](#options) to pass to gray-matter and [js-yaml].
+   * @return {String} Returns a string created by wrapping stringified yaml with delimiters, and appending that to the given string.
+   */
+  export function stringify<O extends GrayMatterOption<string, O>>(
+    file: string | { content: string },
+    data: object,
+    options?: GrayMatterOption<string, O>
+  ): string
+
+  /**
+   * Synchronously read a file from the file system and parse
+   * front matter. Returns the same object as the [main function](#matter).
+   *
+   * ```js
+   * var file = matter.read('./content/blog-post.md');
+   * ```
+   * @param {String} `filepath` file path of the file to read.
+   * @param {Object} `options` [Options](#options) to pass to gray-matter.
+   * @return {Object} Returns [an object](#returned-object) with `data` and `content`
+   */
+  export function read<O extends GrayMatterOption<string, O>>(
+    fp: string,
+    options?: GrayMatterOption<string, O>
+  ): matter.GrayMatterFile<string>
+
+  /**
+   * Returns true if the given `string` has front matter.
+   * @param  {String} `string`
+   * @param  {Object} `options`
+   * @return {Boolean} True if front matter exists.
+   */
+  export function test<O extends matter.GrayMatterOption<string, O>>(
+    str: string,
+    options?: GrayMatterOption<string, O>
+  ): boolean
+
+  /**
+   * Detect the language to use, if one is defined after the
+   * first front-matter delimiter.
+   * @param  {String} `string`
+   * @param  {Object} `options`
+   * @return {Object} Object with `raw` (actual language string), and `name`, the language with whitespace trimmed
+   */
+  export function language<O extends matter.GrayMatterOption<string, O>>(
+    str: string,
+    options?: GrayMatterOption<string, O>
+  ): { name: string; raw: string }
 }
 
 export = matter
diff --git a/index.js b/index.js
index c5330b4..7d49331 100644
--- a/index.js
+++ b/index.js
@@ -1,15 +1,14 @@
 'use strict';
 
-var fs = require('fs');
-var extend = require('extend-shallow');
-var parse = require('./lib/parse');
-var defaults = require('./lib/defaults');
-var stringify = require('./lib/stringify');
-var excerpt = require('./lib/excerpt');
-var engines = require('./lib/engines');
-var toFile = require('./lib/to-file');
-var utils = require('./lib/utils');
-var cache = {};
+const fs = require('fs');
+const sections = require('section-matter');
+const defaults = require('./lib/defaults');
+const stringify = require('./lib/stringify');
+const excerpt = require('./lib/excerpt');
+const engines = require('./lib/engines');
+const toFile = require('./lib/to-file');
+const parse = require('./lib/parse');
+const utils = require('./lib/utils');
 
 /**
  * Takes a string or object with `content` property, extracts
@@ -17,7 +16,7 @@ var cache = {};
  * with `data`, `content` and other [useful properties](#returned-object).
  *
  * ```js
- * var matter = require('gray-matter');
+ * const matter = require('gray-matter');
  * console.log(matter('---\ntitle: Home\n---\nOther stuff'));
  * //=> { data: { title: 'Home'}, content: 'Other stuff' }
  * ```
@@ -28,36 +27,45 @@ var cache = {};
  */
 
 function matter(input, options) {
-  var file = {data: {}, content: input, excerpt: '', orig: input};
-  if (input === '') return file;
+  if (input === '') {
+    return { data: {}, content: input, excerpt: '', orig: input };
+  }
 
-  file = toFile(input);
-  var cached = cache[file.content];
+  let file = toFile(input);
+  const cached = matter.cache[file.content];
 
   if (!options) {
     if (cached) {
-      file = extend({}, cached);
+      file = Object.assign({}, cached);
       file.orig = cached.orig;
       return file;
     }
-    cache[file.content] = file;
+
+    // only cache if there are no options passed. if we cache when options
+    // are passed, we would need to also cache options values, which would
+    // negate any performance benefits of caching
+    matter.cache[file.content] = file;
   }
 
   return parseMatter(file, options);
 }
 
+/**
+ * Parse front matter
+ */
+
 function parseMatter(file, options) {
-  var opts = defaults(options);
-  var open = opts.delimiters[0];
-  var close = '\n' + opts.delimiters[1];
-  var str = file.content;
+  const opts = defaults(options);
+  const open = opts.delimiters[0];
+  const close = '\n' + opts.delimiters[1];
+  let str = file.content;
 
   if (opts.language) {
     file.language = opts.language;
   }
 
   // get the length of the opening delimiter
-  var openLen = open.length;
+  const openLen = open.length;
   if (!utils.startsWith(str, open, openLen)) {
     excerpt(file, opts);
     return file;
@@ -72,17 +80,17 @@ function parseMatter(file, options) {
 
   // strip the opening delimiter
   str = str.slice(openLen);
-  var len = str.length;
+  const len = str.length;
 
   // use the language defined after first delimiter, if it exists
-  var language = matter.language(str, opts);
+  const language = matter.language(str, opts);
   if (language.name) {
     file.language = language.name;
     str = str.slice(language.raw.length);
   }
 
   // get the index of the closing delimiter
-  var closeIndex = str.indexOf(close);
+  let closeIndex = str.indexOf(close);
   if (closeIndex === -1) {
     closeIndex = len;
   }
@@ -90,8 +98,16 @@ function parseMatter(file, options) {
   // get the raw front-matter block
   file.matter = str.slice(0, closeIndex);
 
-  // create file.data by parsing the raw file.matter block
-  file.data = parse(file.language, file.matter, opts);
+  const block = file.matter.replace(/^\s*#[^\n]+/gm, '').trim();
+  if (block === '') {
+    file.isEmpty = true;
+    file.empty = file.content;
+    file.data = {};
+  } else {
+
+    // create file.data by parsing the raw file.matter block
+    file.data = parse(file.language, file.matter, opts);
+  }
 
   // update file.content
   if (closeIndex === len) {
@@ -107,6 +123,10 @@ function parseMatter(file, options) {
   }
 
   excerpt(file, opts);
+
+  if (opts.sections === true || typeof opts.section === 'function') {
+    sections(file, opts.section);
+  }
   return file;
 }
 
@@ -138,9 +158,7 @@ matter.engines = engines;
  */
 
 matter.stringify = function(file, data, options) {
-  if (typeof file === 'string') {
-    file = matter(file, options);
-  }
+  if (typeof file === 'string') file = matter(file, options);
   return stringify(file, data, options);
 };
 
@@ -149,7 +167,7 @@ matter.stringify = function(file, data, options) {
  * front matter. Returns the same object as the [main function](#matter).
  *
  * ```js
- * var file = matter.read('./content/blog-post.md');
+ * const file = matter.read('./content/blog-post.md');
  * ```
  * @param {String} `filepath` file path of the file to read.
  * @param {Object} `options` [Options](#options) to pass to gray-matter.
@@ -158,8 +176,8 @@ matter.stringify = function(file, data, options) {
  */
 
 matter.read = function(filepath, options) {
-  var str = fs.readFileSync(filepath, 'utf8');
-  var file = matter(str, options);
+  const str = fs.readFileSync(filepath, 'utf8');
+  const file = matter(str, options);
   file.path = filepath;
   return file;
 };
@@ -173,8 +191,7 @@ matter.read = function(filepath, options) {
  */
 
 matter.test = function(str, options) {
-  var opts = defaults(options);
-  return utils.startsWith(str, opts.delimiters[0]);
+  return utils.startsWith(str, defaults(options).delimiters[0]);
 };
 
 /**
@@ -186,14 +203,14 @@ matter.test = function(str, options) {
  */
 
 matter.language = function(str, options) {
-  var opts = defaults(options);
-  var open = opts.delimiters[0];
+  const opts = defaults(options);
+  const open = opts.delimiters[0];
 
   if (matter.test(str)) {
     str = str.slice(open.length);
   }
 
-  var language = str.slice(0, str.search(/\r?\n/));
+  const language = str.slice(0, str.search(/\r?\n/));
   return {
     raw: language,
     name: language ? language.trim() : ''
@@ -204,4 +221,8 @@ matter.language = function(str, options) {
  * Expose `matter`
  */
 
+matter.cache = {};
+matter.clearCache = function() {
+  matter.cache = {};
+};
 module.exports = matter;
diff --git a/lib/defaults.js b/lib/defaults.js
index d61da1a..81d9e41 100644
--- a/lib/defaults.js
+++ b/lib/defaults.js
@@ -1,11 +1,10 @@
 'use strict';
 
-var extend = require('extend-shallow');
-var engines = require('./engines');
-var utils = require('./utils');
+const engines = require('./engines');
+const utils = require('./utils');
 
 module.exports = function(options) {
-  var opts = extend({}, options);
+  const opts = Object.assign({}, options);
 
   // ensure that delimiters are an array
   opts.delimiters = utils.arrayify(opts.delims || opts.delimiters || '---');
@@ -14,6 +13,6 @@ module.exports = function(options) {
   }
 
   opts.language = (opts.language || opts.lang || 'yaml').toLowerCase();
-  opts.engines = extend({}, engines, opts.parsers, opts.engines);
+  opts.engines = Object.assign({}, engines, opts.parsers, opts.engines);
   return opts;
 };
diff --git a/lib/engine.js b/lib/engine.js
index 65cc0e0..d8f6c41 100644
--- a/lib/engine.js
+++ b/lib/engine.js
@@ -1,7 +1,7 @@
 'use strict';
 
 module.exports = function(name, options) {
-  var engine = options.engines[name] || options.engines[aliase(name)];
+  let engine = options.engines[name] || options.engines[aliase(name)];
   if (typeof engine === 'undefined') {
     throw new Error('gray-matter engine "' + name + '" is not registered');
   }
diff --git a/lib/engines.js b/lib/engines.js
index a299c08..38f993d 100644
--- a/lib/engines.js
+++ b/lib/engines.js
@@ -1,13 +1,12 @@
 'use strict';
 
-var extend = require('extend-shallow');
-var yaml = require('js-yaml');
+const yaml = require('js-yaml');
 
 /**
  * Default engines
  */
 
-var engines = exports = module.exports;
+const engines = exports = module.exports;
 
 /**
  * YAML
@@ -25,7 +24,7 @@ engines.yaml = {
 engines.json = {
   parse: JSON.parse.bind(JSON),
   stringify: function(obj, options) {
-    var opts = extend({replacer: null, space: 2}, options);
+    const opts = Object.assign({replacer: null, space: 2}, options);
     return JSON.stringify(obj, opts.replacer, opts.space);
   }
 };
diff --git a/lib/excerpt.js b/lib/excerpt.js
index 16a0aac..14d9904 100644
--- a/lib/excerpt.js
+++ b/lib/excerpt.js
@@ -1,9 +1,9 @@
 'use strict';
 
-var defaults = require('./defaults');
+const defaults = require('./defaults');
 
 module.exports = function(file, options) {
-  var opts = defaults(options);
+  const opts = defaults(options);
 
   if (file.data == null) {
     file.data = {};
@@ -13,18 +13,17 @@ module.exports = function(file, options) {
     return opts.excerpt(file, opts);
   }
 
-  var sep = file.data.excerpt_separator || opts.excerpt_separator;
+  const sep = file.data.excerpt_separator || opts.excerpt_separator;
   if (sep == null && (opts.excerpt === false || opts.excerpt == null)) {
     return file;
   }
 
-  var delimiter = sep || opts.delimiters[0];
-  if (typeof opts.excerpt === 'string') {
-    delimiter = opts.excerpt;
-  }
+  const delimiter = typeof opts.excerpt === 'string'
+    ? opts.excerpt
+    : (sep || opts.delimiters[0]);
 
   // if enabled, get the excerpt defined after front-matter
-  var idx = file.content.indexOf(delimiter);
+  const idx = file.content.indexOf(delimiter);
   if (idx !== -1) {
     file.excerpt = file.content.slice(0, idx);
   }
diff --git a/lib/parse.js b/lib/parse.js
index c49e9c4..e10ea9b 100644
--- a/lib/parse.js
+++ b/lib/parse.js
@@ -1,11 +1,11 @@
 'use strict';
 
-var getEngine = require('./engine');
-var defaults = require('./defaults');
+const getEngine = require('./engine');
+const defaults = require('./defaults');
 
 module.exports = function(language, str, options) {
-  var opts = defaults(options);
-  var engine = getEngine(language, opts);
+  const opts = defaults(options);
+  const engine = getEngine(language, opts);
   if (typeof engine.parse !== 'function') {
     throw new TypeError('expected "' + language + '.parse" to be a function');
   }
diff --git a/lib/stringify.js b/lib/stringify.js
index 5d937d4..b4c70a4 100644
--- a/lib/stringify.js
+++ b/lib/stringify.js
@@ -1,9 +1,8 @@
 'use strict';
 
-var extend = require('extend-shallow');
-var typeOf = require('kind-of');
-var getEngine = require('./engine');
-var defaults = require('./defaults');
+const typeOf = require('kind-of');
+const getEngine = require('./engine');
+const defaults = require('./defaults');
 
 module.exports = function(file, data, options) {
   if (data == null && options == null) {
@@ -20,26 +19,24 @@ module.exports = function(file, data, options) {
     }
   }
 
-  var str = file.content;
-  var opts = defaults(options);
+  const str = file.content;
+  const opts = defaults(options);
   if (data == null) {
-    if (!opts.data) {
-      return file;
-    }
+    if (!opts.data) return file;
     data = opts.data;
   }
 
-  var language = file.language || opts.language;
-  var engine = getEngine(language, opts);
+  const language = file.language || opts.language;
+  const engine = getEngine(language, opts);
   if (typeof engine.stringify !== 'function') {
     throw new TypeError('expected "' + language + '.stringify" to be a function');
   }
 
-  data = extend({}, file.data, data);
-  var open = opts.delimiters[0];
-  var close = opts.delimiters[1];
-  var matter = engine.stringify(data, options).trim();
-  var buf = '';
+  data = Object.assign({}, file.data, data);
+  const open = opts.delimiters[0];
+  const close = opts.delimiters[1];
+  const matter = engine.stringify(data, options).trim();
+  let buf = '';
 
   if (matter !== '{}') {
     buf = newline(open) + newline(matter) + newline(close);
diff --git a/lib/to-file.js b/lib/to-file.js
index 8d9a763..799bb5d 100644
--- a/lib/to-file.js
+++ b/lib/to-file.js
@@ -1,8 +1,8 @@
 'use strict';
 
-var typeOf = require('kind-of');
-var stringify = require('./stringify');
-var utils = require('./utils');
+const typeOf = require('kind-of');
+const stringify = require('./stringify');
+const utils = require('./utils');
 
 /**
  * Normalize the given value to ensure an object is returned
@@ -18,45 +18,26 @@ module.exports = function(file) {
     file.data = {};
   }
 
-  if (file.content == null) {
+  // if file was passed as an object, ensure that
+  // "file.content" is set
+  if (file.contents && file.content == null) {
     file.content = file.contents;
   }
 
-  var orig = utils.toBuffer(file.content);
-  Object.defineProperty(file, 'orig', {
-    configurable: true,
-    enumerable: false,
-    writable: true,
-    value: orig
-  });
-
-  Object.defineProperty(file, 'matter', {
-    configurable: true,
-    enumerable: false,
-    writable: true,
-    value: file.matter || ''
-  });
-
-  Object.defineProperty(file, 'language', {
-    configurable: true,
-    enumerable: false,
-    writable: true,
-    value: file.language || ''
-  });
-
-  Object.defineProperty(file, 'stringify', {
-    configurable: true,
-    enumerable: false,
-    writable: true,
-    value: function(data, options) {
-      if (options && options.language) {
-        file.language = options.language;
-      }
-      return stringify(file, data, options);
+  // set non-enumerable properties on the file object
+  utils.define(file, 'orig', utils.toBuffer(file.content));
+  utils.define(file, 'language', file.language || '');
+  utils.define(file, 'matter', file.matter || '');
+  utils.define(file, 'stringify', function(data, options) {
+    if (options && options.language) {
+      file.language = options.language;
     }
+    return stringify(file, data, options);
   });
 
+  // strip BOM and ensure that "file.content" is a string
   file.content = utils.toString(file.content);
+  file.isEmpty = false;
   file.excerpt = '';
   return file;
 };
diff --git a/lib/utils.js b/lib/utils.js
index 4e8270d..96e7ce0 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -1,14 +1,23 @@
 'use strict';
 
-var stripBom = require('strip-bom-string');
-exports.typeOf = require('kind-of');
+const stripBom = require('strip-bom-string');
+const typeOf = require('kind-of');
+
+exports.define = function(obj, key, val) {
+  Reflect.defineProperty(obj, key, {
+    enumerable: false,
+    configurable: true,
+    writable: true,
+    value: val
+  });
+};
 
 /**
  * Returns true if `val` is a buffer
  */
 
 exports.isBuffer = function(val) {
-  return exports.typeOf(val) === 'buffer';
+  return typeOf(val) === 'buffer';
 };
 
 /**
@@ -16,7 +25,7 @@ exports.isBuffer = function(val) {
  */
 
 exports.isObject = function(val) {
-  return exports.typeOf(val) === 'object';
+  return typeOf(val) === 'object';
 };
 
 /**
@@ -24,10 +33,7 @@ exports.isObject = function(val) {
  */
 
 exports.toBuffer = function(input) {
-  if (typeof input === 'string') {
-    return new Buffer(input);
-  }
-  return input;
+  return typeof input === 'string' ? Buffer.from(input) : input;
 };
 
 /**
@@ -35,9 +41,7 @@ exports.toBuffer = function(input) {
  */
 
 exports.toString = function(input) {
-  if (exports.isBuffer(input)) {
-    return stripBom(String(input));
-  }
+  if (exports.isBuffer(input)) return stripBom(String(input));
   if (typeof input !== 'string') {
     throw new TypeError('expected input to be a string or buffer');
   }
diff --git a/package.json b/package.json
index e462841..bdce8c9 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "gray-matter",
   "description": "Parse front-matter from a string or file. Fast, reliable and easy to use. Parses YAML front matter by default, but also has support for YAML, JSON, TOML or Coffee Front-Matter, with options to set custom delimiters. Used by metalsmith, assemble, verb and many other projects.",
-  "version": "3.1.0",
+  "version": "4.0.2",
   "homepage": "https://github.com/jonschlinkert/gray-matter",
   "author": "Jon Schlinkert (https://github.com/jonschlinkert)",
   "contributors": [
@@ -28,29 +28,27 @@
   ],
   "main": "index.js",
   "engines": {
-    "node": ">=0.10.0"
+    "node": ">=6.0"
   },
   "scripts": {
     "test": "mocha"
   },
-  "browser": {
-    "fs": false
-  },
   "dependencies": {
-    "extend-shallow": "^2.0.1",
-    "js-yaml": "^3.10.0",
-    "kind-of": "^5.0.2",
+    "js-yaml": "^3.11.0",
+    "kind-of": "^6.0.2",
+    "section-matter": "^1.0.0",
     "strip-bom-string": "^1.0.0"
   },
   "devDependencies": {
-    "ansi-magenta": "^0.1.1",
+    "ansi-green": "^0.1.1",
     "benchmarked": "^2.0.0",
-    "coffee-script": "^1.12.7",
+    "coffeescript": "^2.2.3",
     "delimiter-regex": "^2.0.0",
-    "front-matter": "^2.2.0",
+    "extend-shallow": "^3.0.2",
+    "front-matter": "^2.3.0",
     "gulp-format-md": "^1.0.0",
     "minimist": "^1.2.0",
-    "mocha": "^4.0.0",
+    "mocha": "^3.5.3",
     "toml": "^2.3.3",
     "vinyl": "^2.1.0",
     "write": "^1.0.3"
@@ -87,7 +85,15 @@
     "yaml",
     "yfm"
   ],
+  "browser": {
+    "fs": false
+  },
   "typings": "gray-matter.d.ts",
+  "eslintConfig": {
+    "rules": {
+      "no-console": 0
+    }
+  },
   "verb": {
     "toc": false,
     "layout": "default",
diff --git a/test/matter-empty.js b/test/matter-empty.js
new file mode 100644
index 0000000..edc5b7e
--- /dev/null
+++ b/test/matter-empty.js
@@ -0,0 +1,35 @@
+'use strict';
+
+require('mocha');
+var assert = require('assert');
+var utils = require('../lib/utils');
+var matter = require('..');
+
+describe('gray-matter', function() {
+  it('should work with empty front-matter', function() {
+    var file1 = matter('---\n---\nThis is content');
+    assert.equal(file1.content, 'This is content');
+    assert.deepEqual(file1.data, {});
+
+    var file2 = matter('---\n\n---\nThis is content');
+    assert.equal(file2.content, 'This is content');
+    assert.deepEqual(file2.data, {});
+
+    var file3 = matter('---\n\n\n\n\n\n---\nThis is content');
+    assert.equal(file3.content, 'This is content');
+    assert.deepEqual(file3.data, {});
+  });
+
+  it('should add content with empty front matter to file.empty', function() {
+    assert.deepEqual(matter('---\n---').empty, '---\n---');
+  });
+
+  it('should update file.isEmpty to true', function() {
+    assert.deepEqual(matter('---\n---').isEmpty, true);
+  });
+
+  it('should work when front-matter has comments', function() {
+    const fixture = '---\n # this is a comment\n# another one\n---';
+    assert.deepEqual(matter(fixture).empty, fixture);
+  });
+});
diff --git a/test/matter.js b/test/matter.js
index 2f86ff7..9e40393 100644
--- a/test/matter.js
+++ b/test/matter.js
@@ -21,24 +21,25 @@ describe('gray-matter', function() {
     assert.equal(actual.orig.toString(), fixture);
   });
 
-  it('should work with empty front-matter', function() {
-    var file1 = matter('---\n---\nThis is content');
-    assert.equal(file1.content, 'This is content');
-    assert.deepEqual(file1.data, {});
+  it('extra characters should throw parsing errors', function() {
+    assert.throws(function() {
+      matter('---whatever\nabc: xyz\n---');
+    });
+  });
 
-    var file2 = matter('---\n\n---\nThis is content');
-    assert.equal(file2.content, 'This is content');
-    assert.deepEqual(file2.data, {});
+  it('boolean yaml types should still return the empty object', function() {
+    var actual = matter('--- true\n---');
+    assert.deepEqual(actual.data, {});
+  });
 
-    var file3 = matter('---\n\n\n\n\n\n---\nThis is content');
-    assert.equal(file3.content, 'This is content');
-    assert.deepEqual(file3.data, {});
+  it('string yaml types should still return the empty object', function() {
+    var actual = matter('--- true\n---');
+    assert.deepEqual(actual.data, {});
   });
 
-  it('should throw parsing errors', function() {
-    assert.throws(function() {
-      matter('---whatever\nabc: xyz\n---');
-    });
+  it('number yaml types should still return the empty object', function() {
+    var actual = matter('--- 42\n---');
+    assert.deepEqual(actual.data, {});
   });
 
   it('should throw an error when a string is not passed:', function() {
diff --git a/test/parse-coffee.js b/test/parse-coffee.js
index 059946d..517bde2 100644
--- a/test/parse-coffee.js
+++ b/test/parse-coffee.js
@@ -12,7 +12,7 @@ var assert = require('assert');
 var extend = require('extend-shallow');
 var matter = require('../');
 var fixture = path.join.bind(path, __dirname, 'fixtures');
-var coffee = require('coffee-script');
+var coffee = require('coffeescript');
 var defaults = {
   engines: {
     coffee: {
diff --git a/test/parse-cson.js b/test/parse-cson.js
index ed3fa53..152def5 100644
--- a/test/parse-cson.js
+++ b/test/parse-cson.js
@@ -11,7 +11,7 @@ var path = require('path');
 var assert = require('assert');
 var matter = require('..');
 var extend = require('extend-shallow');
-var coffee = require('coffee-script');
+var coffee = require('coffeescript');
 var fixture = path.join.bind(path, __dirname, 'fixtures');
 var defaults = {
   engines: {