diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 0000000..8c52ff9
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,12 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+indent_style = space
+indent_size = 2
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.md]
+trim_trailing_whitespace = false
diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000..176a458
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1 @@
+* text=auto
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..76b1021
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+.nyc_output
+coverage
+node_modules
diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 0000000..2de7d16
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,8 @@
+dist: trusty
+branches:
+  except: /^v\d/
+language: node_js
+node_js: node
+after_script:
+  - npm install coveralls
+  - nyc report --reporter=text-lcov | coveralls
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..0b0cb16
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,20 @@
+The MIT License (MIT)
+
+Copyright (c) 2017 Shinnosuke Watanabe
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..788311a
--- /dev/null
+++ b/README.md
@@ -0,0 +1,89 @@
+# postcss-error-to-vscode-diagnostic
+
+[![NPM version](https://img.shields.io/npm/v/postcss-error-to-vscode-diagnostic.svg)](https://www.npmjs.com/package/postcss-error-to-vscode-diagnostic)
+[![Build Status](https://travis-ci.org/shinnn/postcss-error-to-vscode-diagnostic.svg?branch=master)](https://travis-ci.org/shinnn/postcss-error-to-vscode-diagnostic)
+[![Coverage Status](https://img.shields.io/coveralls/shinnn/postcss-error-to-vscode-diagnostic.svg)](https://coveralls.io/github/shinnn/postcss-error-to-vscode-diagnostic?branch=master)
+
+Convert a [`CssSyntaxError`](http://api.postcss.org/CssSyntaxError.html) of [PostCSS](http://postcss.org/) into a [diagnostic](https://code.visualstudio.com/docs/extensionAPI/vscode-api#Diagnostic) of [Visual Studio Code](https://code.visualstudio.com/)
+
+```javascript
+const postcss = require('postcss');
+const postcssErrorToVscodeDiagnostic = require('postcss-error-to-vscode-diagnostic');
+
+const {error} = postcss().process(`
+  div {
+    color::red
+  }
+`);
+/* CssSyntaxError {
+  reason: 'Double colon',
+  line: 3,
+  column: 11,
+  ...
+} */
+
+stylelintWarningToVscodeDiagnostic(error);
+/* {
+  message: 'Double colon (syntax error)',
+  severity: 1,
+  range: {
+    start: {
+      line: 2,
+      column: 10
+    },
+    end: {
+      line: 2,
+      column: 10
+    }
+  }
+} */
+```
+
+## Installation
+
+[Use npm.](https://docs.npmjs.com/cli/install)
+
+```
+npm install postcss-error-to-vscode-diagnostic
+```
+
+## API
+
+```javascript
+const postcssErrorToVscodeDiagnostic = require('postcss-error-to-vscode-diagnostic');
+```
+
+### postcssErrorToVscodeDiagnostic(*error* [, *additionalProperties*])
+
+*error*: [`CssSyntaxError`](https://github.com/postcss/postcss/blob/ea3290a31d28dbc1502e1f03fddb1c927dcdbc35/lib/css-syntax-error.es6#L34)  
+*additionalProperties*: `Object`  
+Return: `Object` (VS Code [diagnostic](https://github.com/Microsoft/vscode-languageserver-node/blob/release/3.0.3/types/src/main.ts#L161-L192))
+
+The returned diagnostic has [`message`](https://github.com/Microsoft/vscode-languageserver-node/blob/2f9d6055a77d8e9d31ecda03f8b1c54dd5ea0246/types/src/main.ts#L188-L191), [`range`](https://github.com/Microsoft/vscode-languageserver-node/blob/2f9d6055a77d8e9d31ecda03f8b1c54dd5ea0246/types/src/main.ts#L166-L169) and [`severity`](https://github.com/Microsoft/vscode-languageserver-node/blob/2f9d6055a77d8e9d31ecda03f8b1c54dd5ea0246/types/src/main.ts#L171-L175) by default.
+
+All properties of the second argument will be [assigned](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object/assign) to the return value. For example you can add a missing [`source`](https://github.com/Microsoft/vscode-languageserver-node/blob/2f9d6055a77d8e9d31ecda03f8b1c54dd5ea0246/types/src/main.ts#L182-L186) property as below:
+
+```javascript
+const error = postcss().process('foo');
+
+postcssErrorToVscodeDiagnostic(error);
+/* {
+  message: 'Unknown word (syntax error)',
+  severity: 1,
+  range: { ... }
+} */
+
+postcssErrorToVscodeDiagnostic(error, {source: 'my-awesome-linter'});
+/* {
+  message: 'Unknown word (syntax error)',
+  severity: 1,
+  range: { ... },
+  source: 'my-awesome-linter'
+} */
+```
+
+## License
+
+Copyright (c) 2017 [Shinnosuke Watanabe](https://github.com/shinnn)
+
+Licensed under [the MIT License](./LICENSE).
diff --git a/index.js b/index.js
new file mode 100644
index 0000000..0f25894
--- /dev/null
+++ b/index.js
@@ -0,0 +1,46 @@
+/*!
+ * postcss-error-to-vscode-diagnostic | MIT (c) Shinnosuke Watanabe
+ * https://github.com/shinnn/postcss-error-to-vscode-diagnostic
+*/
+'use strict';
+
+const {inspect} = require('util');
+
+module.exports = function postcssErrorToVscodeDiagnostic(...args) {
+  const argLen = args.length;
+
+  if (argLen !== 1 && argLen !== 2) {
+    throw new TypeError(`Expected 1 or 2 arguments (object[, object]), but got ${
+      argLen === 0 ? 'no' : argLen
+    } arguments instead.`);
+  }
+
+  const error = args[0];
+
+  if (error === null || typeof error !== 'object' || error.name !== 'CssSyntaxError') {
+    throw new TypeError(`Expected an instance of postcss's CssSyntaxError, but got ${
+      inspect(error)
+    } instead. http://api.postcss.org/CssSyntaxError.html`);
+  }
+
+  const position = {
+    line: error.line - 1,
+    column: error.column - 1
+  };
+
+  const diagnostic = {
+    message: `${error.reason} (syntax error)`,
+    // https://github.com/Microsoft/vscode-languageserver-node/blob/release/3.0.3/types/src/main.ts#L144
+    severity: 1,
+    range: {
+      start: position,
+      end: position
+    }
+  };
+
+  if (argLen === 1) {
+    return diagnostic;
+  }
+
+  return Object.assign(diagnostic, args[1]);
+};
diff --git a/package.json b/package.json
new file mode 100644
index 0000000..1a85765
--- /dev/null
+++ b/package.json
@@ -0,0 +1,37 @@
+{
+  "name": "postcss-error-to-vscode-diagnostic",
+  "version": "1.0.0",
+  "description": "Convert a CssSyntaxError of PostCSS into a diagnostic of Visual Studio Code",
+  "repository": "shinnn/postcss-error-to-vscode-diagnostic",
+  "author": "Shinnosuke Watanabe (https://github.com/shinnn)",
+  "scripts": {
+    "pretest": "eslint --fix --format=codeframe index.js test.js",
+    "test": "nyc --reporter=html --reporter=text node test.js"
+  },
+  "license": "MIT",
+  "files": [
+    "index.js"
+  ],
+  "keywords": [
+    "css",
+    "postcss",
+    "vscode",
+    "syntax",
+    "error",
+    "diagnostic",
+    "convert",
+    "compatibility",
+    "interface",
+    "object"
+  ],
+  "devDependencies": {
+    "@shinnn/eslint-config-node": "^3.0.0",
+    "eslint": "^3.15.0",
+    "nyc": "^10.1.2",
+    "postcss": "^5.2.14",
+    "tape": "^4.6.3"
+  },
+  "eslintConfig": {
+    "extends": "@shinnn/node"
+  }
+}
diff --git a/test.js b/test.js
new file mode 100644
index 0000000..537a9e5
--- /dev/null
+++ b/test.js
@@ -0,0 +1,78 @@
+'use strict';
+
+const fn = require('.');
+const postcss = require('postcss');
+const test = require('tape');
+
+test('postcssErrorToVscodeDiagnostic()', t => {
+  t.deepEqual(
+    fn(postcss().process('a').error),
+    {
+      message: 'Unknown word (syntax error)',
+      range: {
+        end: {
+          column: 0,
+          line: 0
+        },
+        start: {
+          column: 0,
+          line: 0
+        }
+      },
+      severity: 1
+    },
+    'should convert a CssSyntaxError into a VS Code diagnostic.'
+  );
+
+  t.deepEqual(
+    fn(postcss().process('\n  }').error, {source: 'awesome-css-processor'}),
+    {
+      message: 'Unexpected } (syntax error)',
+      range: {
+        end: {
+          line: 1,
+          column: 2
+        },
+        start: {
+          line: 1,
+          column: 2
+        }
+      },
+      severity: 1,
+      source: 'awesome-css-processor'
+    },
+    'should override values with the second argument.'
+  );
+
+  t.throws(
+    () => fn(),
+    /^TypeError.*Expected 1 or 2 arguments \(object\[, object]\), but got no arguments instead\./,
+    'should throw an error when it takes no arguments.'
+  );
+
+  t.throws(
+    () => fn({}, {}, {}),
+    /^TypeError.*Expected 1 or 2 arguments \(object\[, object]\), but got 3 arguments instead\./,
+    'should throw an error when it takes too many arguments.'
+  );
+
+  t.throws(
+    () => fn(null),
+    /^TypeError.*Expected an instance of postcss's CssSyntaxError, but got null instead\. /,
+    'should throw an error when it takes null.'
+  );
+
+  t.throws(
+    () => fn(Symbol('Hi')),
+    /^TypeError.*Expected an instance of postcss's CssSyntaxError, but got Symbol\(Hi\) instead\. /,
+    'should throw an error when it takes a non-object value.'
+  );
+
+  t.throws(
+    () => fn({foo: 'bar'}),
+    /^TypeError.*Expected an instance of postcss's CssSyntaxError, but got { foo: 'bar' } instead\. /,
+    'should throw an error when the frist argument is not a CssSyntaxError.'
+  );
+
+  t.end();
+});