feat: Initial commit (#1)

.editorconfig

@@ -0,0 +1,13 @@
+# editorconfig.org
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[*.snap]
+trim_trailing_whitespace = false

.eslintrc

@@ -0,0 +1,7 @@
+{
+  "extends": "seek",
+  "rules": {
+    "no-console": 0,
+    "no-sync": 0
+  }
+}

.github/CODEOWNERS

@@ -0,0 +1,5 @@
+# See https://help.github.com/articles/about-codeowners/ for more info
+# Each line is a file pattern followed by one or more owners.
+
+# These owners will be the default owners for everything in the repo.
+*       @front-end-contributors

.gitignore

@@ -0,0 +1 @@
+node_modules

.npmrc

@@ -0,0 +1 @@
+package-lock=false

.nvmrc

@@ -0,0 +1 @@
+lts/*

.prettierrc

@@ -0,0 +1,3 @@
+{
+  "singleQuote": true
+}

.travis.yml

@@ -0,0 +1,10 @@
+language: node_js
+notifications:
+  email: false
+before_script:
+  - npm prune
+after_success:
+  - npm run semantic-release
+branches:
+  except:
+    - /^v\d+\.\d+\.\d+$/

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2018 SEEK
+
+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.

README.md

@@ -1,3 +1,67 @@
+[![Build Status](https://img.shields.io/travis/seek-oss/gitignore-ensure/master.svg?style=flat-square)](http://travis-ci.org/seek-oss/gitignore-ensure) [![npm](https://img.shields.io/npm/v/gitignore-ensure.svg?style=flat-square)](https://www.npmjs.com/package/gitignore-ensure) [![semantic-release](https://img.shields.io/badge/%20%20%F0%9F%93%A6%F0%9F%9A%80-semantic--release-e10079.svg?style=flat-square)](https://github.com/semantic-release/semantic-release) [![Commitizen friendly](https://img.shields.io/badge/commitizen-friendly-brightgreen.svg?style=flat-square)](http://commitizen.github.io/cz-cli/)
+
 # gitignore-ensure
 
-Ensure the presence of paths within a project's gitignore
+Ensure the presence of patterns within a project's gitignore.
+
+## Usage
+
+```js
+const gitignoreEnsure = require('gitignore-ensure');
+
+await gitignoreEnsure({
+  patterns: ['node_modules', 'output']
+});
+```
+
+### Options
+
+#### filepath (string, default: '<cwd>/.gitignore')
+
+Path to the `.gitignore` file to be used.
+
+#### patterns (?Array\<string>)
+
+An array of patterns to ensure are present in the specified `.gitignore` file. Any pattern that already exists in the file will be appended with the [comment](#comment). All new patterns will be appended to the bottom of the file.
+
+<a id="comment">
+
+#### comment (?string)
+
+Appended to each pattern that is being ensured to indicate what is programmatically being controlled.
+
+```js
+const gitignoreEnsure = require('gitignore-ensure');
+
+await gitignoreEnsure({
+  patterns: ['node_modules', 'output'],
+  comment: 'managed'
+});
+
+// =>
+// node_modules # managed
+// output # managed
+//
+```
+
+#### dryRun (?boolean, default: false)
+
+The file at the input path will not be updated, instead the intended output will be returned.
+
+```js
+const gitignoreEnsure = require('gitignore-ensure');
+
+const result = await gitignoreEnsure({
+  patterns: ['node_modules', 'output'],
+  dryRun: true
+});
+
+// result:
+// node_modules
+// output
+//
+```
+
+## License
+
+MIT.

index.js

@@ -0,0 +1,43 @@
+const fs = require('fs');
+const path = require('path');
+const { promisify } = require('util');
+
+const writeFile = promisify(fs.writeFile);
+const readFile = promisify(fs.readFile);
+
+const write = async (filepath, output, dryRun) => {
+  if (!dryRun) {
+    await writeFile(filepath, output);
+  }
+  return output;
+};
+
+module.exports = async ({
+  patterns = [],
+  comment = '',
+  filepath = path.resolve(process.cwd(), '.gitignore'),
+  dryRun = false
+}) => {
+  const commented = str => (comment ? `${str} # ${comment}` : str);
+
+  const managed = patterns.sort();
+  const contents = await readFile(filepath, 'utf-8');
+  const current = contents.split(/\r?\n/);
+
+  const corrected = current.map(
+    pattern => (managed.includes(pattern) ? commented(pattern) : pattern)
+  );
+
+  const additions = managed
+    .filter(pattern => !corrected.includes(commented(pattern)))
+    .map(commented);
+
+  const outputPatterns = corrected.concat(additions);
+  const output = `${outputPatterns.join('\n')}${
+    outputPatterns[outputPatterns.length - 1] === '' ? '' : '\n'
+  }`;
+
+  return current.join('\n') !== output
+    ? write(filepath, output, dryRun)
+    : current.join('\n');
+};

package.json

@@ -0,0 +1,58 @@
+{
+  "name": "gitignore-ensure",
+  "version": "0.0.0-development",
+  "description": "Ensure the presence of patterns within a project's gitignore",
+  "main": "index.js",
+  "scripts": {
+    "commit": "git-cz",
+    "semantic-release": "semantic-release",
+    "pretest": "eslint .",
+    "test": "jest"
+  },
+  "jest": {
+    "testEnvironment": "node"
+  },
+  "husky": {
+    "hooks": {
+      "commit-msg": "commitlint --edit --extends seek",
+      "pre-commit": "lint-staged"
+    }
+  },
+  "lint-staged": {
+    "*.js": [
+      "prettier --write",
+      "git add"
+    ]
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/seek-oss/gitignore-ensure.git"
+  },
+  "author": "SEEK",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/seek-oss/gitignore-ensure/issues"
+  },
+  "homepage": "https://github.com/seek-oss/gitignore-ensure#readme",
+  "devDependencies": {
+    "@commitlint/cli": "^7.2.1",
+    "commitizen": "^3.0.2",
+    "commitlint-config-seek": "^1.0.0",
+    "cz-conventional-changelog": "^2.1.0",
+    "eslint": "^5.7.0",
+    "eslint-config-seek": "^3.2.1",
+    "husky": "^1.1.2",
+    "jest": "^23.6.0",
+    "lint-staged": "^7.3.0",
+    "prettier": "^1.14.3",
+    "semantic-release": "^15.10.3"
+  },
+  "release": {
+    "success": false
+  },
+  "config": {
+    "commitizen": {
+      "path": "./node_modules/cz-conventional-changelog"
+    }
+  }
+}