v1.0.0 Initial Release

#### Features

- Package exports a single function, `deepMapKeys()`

#### Development

- Added tests written in CoffeeScript
- Set up CI and automatic deployment via Travis
- Added configuration files, e.g. `.gitignore`, `.travis.yml`

#### Documentation

- All functionality documented in `README.md`
- MIT License added

.editorconfig

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+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true

.eslintrc.yml

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+extends: eslint:recommended
+parserOptions:
+  ecmaVersion: 5
+env:
+  node: true

.gitignore

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+/coverage/
+/node_modules/
+/npm-debug.log

.npmignore

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+/coverage/
+/test/
+/.editorconfig
+/.eslintrc.yml
+/.gitignore
+/.travis.yml

.travis.yml

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+language: node_js
+node_js:
+  - "6"
+  - "4"
+  - "0.12"
+  - "0.10"
+after_success:
+  - npm run coveralls
+deploy:
+  provider: npm
+  email:
+    secure: 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
+  api_key:
+    secure: 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
+  skip_cleanup: true
+  on:
+    repo: akim-mcmath/deep-map-keys
+    node: "4"
+    tags: true

LICENSE

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+Copyright (c) 2016 Akim McMath
+
+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

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+# deep-map-keys
+
+[![Version][version-badge]][npm]
+[![License][license-badge]][license]
+[![Build][build-badge]][travis]
+[![Coverage][coverage-badge]][coveralls]
+[![Dependencies][dependencies-badge]][gemnasium]
+
+Recurses through a JSON-like object and transforms its keys, returning a new object.
+
+## Install
+
+Install via [npm][npm].
+
+```sh
+npm install --save deep-map-keys
+```
+
+## Usage
+
+Suppose we want to change the keys of an object from [snake case][snake-case] to
+[camel case][camel-case]. We can do something like this:
+
+```js
+const deepMapKeys = require('deep-map-keys');
+
+let comment = {
+  comment_id: 42,
+  user_id: 1024,
+  user_name: 'Mufasa',
+  content: 'You deliberately disobeyed me.',
+  viewed_by: [
+    { user_id: 3820, user_name: 'Zazu' },
+    { user_id: 8391, user_name: 'Rafiki' }
+  ]
+};
+
+let result = deepMapKeys(comment, key => {
+  return key.replace(/_(\w)/g, (match, char) => char.toUpperCase());
+});
+
+console.log(result); /*
+{
+  commentId: 42,
+  userId: 1024,
+  userName: 'Mufasa',
+  content: 'You deliberately disobeyed me.',
+  viewedBy: [
+    { userId: 3820, userName: 'Rafiki' },
+    { userId: 8391, userName: 'Zazu' }
+  ]
+};
+*/
+```
+
+## API
+
+### `deepMapKeys(object, transformFn, [options])`
+
+Applies `transformFn` to each key in an object. Keys are visited recursively,
+so nested keys will be transformed. A new object is always returned; the
+original object is unmodified.
+
+##### object
+
+`object`
+
+The object whose keys are to be transformed. This object may be an `Array`.
+
+##### transformFn
+
+`function`
+
+The function to call for each key. The return value of the function
+determines the transformed value. The function is called with a single
+argument:
+
+* **key**: The key being transformed.
+
+##### options
+
+`object` (optional)
+
+An options object. The following options are accepted:
+
+* **thisArg**: Sets the value of `this` within `transformFn`.
+
+#### Returns
+
+`object`
+
+Returns a new object.
+
+## License
+
+Copyright © 2016 Akim McMath. Licensed under the [MIT License][license].
+
+[version-badge]: https://img.shields.io/npm/v/deep-map-keys.svg?style=flat-square
+[license-badge]: https://img.shields.io/npm/l/deep-map-keys.svg?style=flat-square
+[build-badge]: https://img.shields.io/travis/akim-mcmath/deep-map-keys/master.svg?style=flat-square
+[coverage-badge]: https://img.shields.io/coveralls/akim-mcmath/deep-map-keys/master.svg?style=flat-square&service=github
+[dependencies-badge]: https://img.shields.io/gemnasium/akim-mcmath/deep-map-keys.svg?style=flat-square
+[npm]: https://www.npmjs.com/package/deep-map-keys
+[license]: LICENSE
+[travis]: https://travis-ci.org/akim-mcmath/deep-map-keys
+[coveralls]: https://coveralls.io/github/akim-mcmath/deep-map-keys?branch=master
+[gemnasium]: https://gemnasium.com/akim-mcmath/deep-map-keys
+[snake-case]: https://en.wikipedia.org/wiki/Snake_case
+[camel-case]: https://en.wikipedia.org/wiki/CamelCase

lib/index.js

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+'use strict';
+
+var isArray = Array.isArray;
+
+function deepMapKeys(obj, fn, opts) {
+  opts = opts || {};
+
+  if (!fn) {
+    err(Error, 'transformFn must be defined');
+  } else if (!isFunction(fn)) {
+    err(TypeError, 'transformFn must be a function');
+  } else if (!isObject(opts)) {
+    err(TypeError, 'options must be an object or undefined');
+  }
+
+  return map(obj, fn, opts);
+}
+
+function map(value, fn, opts) {
+  return isArray(value) ? mapArray(value, fn, opts) :
+    isObject(value) ? mapObject(value, fn, opts) :
+    value;
+}
+
+function mapArray(arr, fn, opts) {
+  var result = [];
+  var len = arr.length;
+
+  for (var i = 0; i < len; i++) {
+    result.push(map(arr[i], fn, opts));
+  }
+
+  return result;
+}
+
+function mapObject(obj, fn, opts) {
+  var result = {};
+
+  for (var key in obj) {
+    result[fn.call(opts.thisArg, key)] = map(obj[key], fn, opts);
+  }
+
+  return result;
+}
+
+function isFunction(value) {
+  return typeof value === 'function';
+}
+
+function isObject(value) {
+  return typeof value === 'object' || isFunction(value);
+}
+
+function err(ctor, msg) {
+  var e = new ctor(msg);
+  Error.captureStackTrace(e, deepMapKeys);
+  throw e;
+}
+
+module.exports = deepMapKeys;

package.json

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+{
+  "name": "deep-map-keys",
+  "version": "1.0.0",
+  "description": "Transforms keys of a JSON-like object",
+  "main": "lib/index.js",
+  "scripts": {
+    "test:lint": "eslint lib",
+    "test:unit": "istanbul cover _mocha",
+    "test": "npm run test:lint && npm run test:unit",
+    "coveralls": "cat coverage/lcov.info | coveralls"
+  },
+  "engines": {
+    "node": ">=0.10"
+  },
+  "keywords": [
+    "map",
+    "keys",
+    "deep",
+    "recursive",
+    "nested",
+    "object",
+    "array",
+    "json"
+  ],
+  "author": "Akim McMath <[email protected]>",
+  "license": "MIT",
+  "devDependencies": {
+    "chai": "^3.5.0",
+    "coffee-script": "^1.10.0",
+    "coveralls": "^2.11.9",
+    "eslint": "^2.12.0",
+    "istanbul": "^0.4.3",
+    "mocha": "^2.5.3",
+    "sinon": "^1.17.4",
+    "sinon-chai": "^2.8.0"
+  },
+  "dependencies": {},
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/akim-mcmath/deep-map-keys.git"
+  },
+  "bugs": {
+    "url": "https://github.com/akim-mcmath/deep-map-keys/issues"
+  },
+  "homepage": "https://github.com/akim-mcmath/deep-map-keys#readme"
+}

test/index.coffee

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+chai = require 'chai'
+sinonChai = require 'sinon-chai'
+sinon = require 'sinon'
+deepMapKeys = require '../lib'
+
+before ->
+  chai.use sinonChai
+  chai.should()
+
+err = (fn, ctor) ->
+  fn.should.throw ctor
+
+describe 'deepMapKeys(object, transformFn, [options])', ->
+  snakeToCamel = null
+  camelMap = null
+
+  beforeEach ->
+    snakeToCamel = sinon.spy (str) ->
+      str.replace /_(\w)/g, (match, char) ->
+         char.toUpperCase()
+
+    camelMap = (object, options) ->
+      deepMapKeys object, snakeToCamel, options
+
+  it 'is the main module', ->
+    deepMapKeys.should.equal require('..')
+
+  it 'is a function', ->
+    deepMapKeys.should.be.a 'function'
+
+  context 'simple object is passed', ->
+
+    it 'transforms keys', ->
+      camelMap
+        user_id: 42
+        user_name: 'Mufasa'
+      .should.deep.equal
+        userId: 42
+        userName: 'Mufasa'
+
+  context 'nested object is passed', ->
+
+    it 'transforms keys', ->
+      camelMap
+        user_info:
+          user_id: 42
+          user_name: 'Mufasa'
+      .should.deep.equal
+        userInfo:
+          userId: 42
+          userName: 'Mufasa'
+
+  context 'complex object is passed', ->
+
+    it 'transforms keys', ->
+      camelMap
+        user_id: 42
+        user_name: 'Mufasa'
+        viewed_by: [
+          user_id: 100, user_name: 'Rafiki'
+        ,
+          user_id: 101, user_name: 'Zazu'
+        ]
+      .should.deep.equal
+        userId: 42
+        userName: 'Mufasa'
+        viewedBy: [
+          userId: 100, userName: 'Rafiki'
+        ,
+          userId: 101, userName: 'Zazu'
+        ]
+
+  context 'complex array is passed', ->
+
+    it 'transforms keys', ->
+      camelMap [
+        user_id: 100, user_name: 'Rafiki'
+      ,
+        user_id: 101, user_name: 'Zazu'
+      ]
+      .should.deep.equal [
+        userId: 100, userName: 'Rafiki'
+      ,
+        userId: 101, userName: 'Zazu'
+      ]
+
+  context '@options.thisArg is set', ->
+
+    it 'sets context in @transformFn', ->
+      camelMap({user_id: 41}, {thisArg: 42})
+      snakeToCamel.should.have.been.calledOn 42
+
+  context 'non-object is passed as @options', ->
+
+    it 'throws TypeError', ->
+      err((-> camelMap({user_id: 42}, 42)), TypeError)
+
+  context 'non-function is passed as @transformFn', ->
+
+    it 'throws TypeError', ->
+      err((-> deepMapKeys({user_id: 42}, 42)), TypeError)
+
+  context 'undefined @transformFn', ->
+
+    it 'throws Error', ->
+      err((-> deepMapKeys({user_id: 42})), Error)
+
+  describe 'return value', ->
+
+    it 'is a new object', ->
+      obj = user_id: 42
+      camelMap(obj).should.not.equal obj
+      obj.should.deep.equal user_id: 42