kylejeske/flatten.js

## flatten.js
/**
 * Takes a deeply nested object, `source`, and returns an object with
 * dot-separated paths pointing to all primitive values from `source`.
 *
 * Examples:
 *
 *   flatten({ foo: { bar: 1 } })
 *     //=> { 'foo.bar': 1 }
 *
 *   flatten({ foo: [{ bar: 1 }, { bar: 2 }] })
 *     //=> { 'foo.0.bar': 1, 'foo.1.bar': 2 }
 */
function flatten(source) {
  // hashtable .. sort of
  let container = {};
  function updateKey(key, data) {
    if (container.hasOwnProperty(key) === true) {
          container[key] = [].concat(container[key], data);
      } else {
          container[key] = data;
      }
  }
  // traverseObject ([object], string: optional)
  function traverseObject (o, k) {
    // edge-case for null objects {'foo.bar':null}
    if (typeof o == "object" && o == null) {
      updateKey(k, o);
    }
    for (var prop in o) {
      let key = prop;
      if (typeof k != "undefined") {
        key = [k, prop].join(".");
      }
      if (typeof o[prop] == "array" || typeof o[prop] == "object") {
        traverseObject(o[prop], key);
      } else {
        updateKey(key, o[prop]);
      }
    }
    return container;
  };
  return traverseObject(source);
}

## flatten.test.html
<!DOCTYPE HTML>
<html>
  <head>
    <title>Elastic Coding Exercise</title>
    <link href="https://cdnjs.cloudflare.com/ajax/libs/mocha/2.2.5/mocha.css" rel="stylesheet" />
  </head>
  <body>
    <div id="mocha"></div>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/mocha/2.2.5/mocha.js"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/chai/2.3.0/chai.js"></script>
    <script src="flatten.js"></script>
    <script src="test.flatten.js"></script>
  </body>
</html>

## test.flatten.js
mocha.setup('bdd');
const expect = chai.expect;

describe('flatten()', function () {
	it('should flatten a simple nested object', function () {
		const source = {
			foo: {
				bar: 1
			}
		};

		const expected = {
			'foo.bar': 1
		};

		expect(flatten(source)).to.deep.equal(expected);
	});

	it('should flatten an object with nested arrays', function () {
		const source = {
			foo: [{
				bar: 1
			}, {
				bar: 2
			}]
		};

		const expected = {
			'foo.0.bar': 1,
			'foo.1.bar': 2
		};

		expect(flatten(source)).to.deep.equal(expected);
	});

	it('should flatten a complex nested object', function () {
		const source = {
			a: 1,
			b: {
				c: true,
				d: {
					e: 'foo'
				}
			},
			f: false,
			g: ['red', 'green', 'blue'],
			h: [{
				i: 2,
				j: 3
			}]
		};

		const expected = {
			'a': 1,
			'b.c': true,
			'b.d.e': 'foo',
			'f': false,
			'g.0': 'red',
			'g.1': 'green',
			'g.2': 'blue',
			'h.0.i': 2,
			'h.0.j': 3
		};

		expect(flatten(source)).to.deep.equal(expected);
	});

	it('should flatten an object with null values', function () {
		const source = {
			foo: {
				bar: null
			}
		};

		const expected = {
			'foo.bar': null
		};

		expect(flatten(source)).to.deep.equal(expected);
	});
});

mocha.run();
	/**
	* Takes a deeply nested object, `source`, and returns an object with
	* dot-separated paths pointing to all primitive values from `source`.
	*
	* Examples:
	*
	* flatten({ foo: { bar: 1 } })
	* //=> { 'foo.bar': 1 }
	*
	* flatten({ foo: [{ bar: 1 }, { bar: 2 }] })
	* //=> { 'foo.0.bar': 1, 'foo.1.bar': 2 }
	*/
	function flatten(source) {
	// hashtable .. sort of
	let container = {};
	function updateKey(key, data) {
	if (container.hasOwnProperty(key) === true) {
	container[key] = [].concat(container[key], data);
	} else {
	container[key] = data;
	}
	}
	// traverseObject ([object], string: optional)
	function traverseObject (o, k) {
	// edge-case for null objects {'foo.bar':null}
	if (typeof o == "object" && o == null) {
	updateKey(k, o);
	}
	for (var prop in o) {
	let key = prop;
	if (typeof k != "undefined") {
	key = [k, prop].join(".");
	}
	if (typeof o[prop] == "array" \|\| typeof o[prop] == "object") {
	traverseObject(o[prop], key);
	} else {
	updateKey(key, o[prop]);
	}
	}
	return container;
	};
	return traverseObject(source);
	}
	<!DOCTYPE HTML>
	<html>
	<head>
	<title>Elastic Coding Exercise</title>
	<link href="https://cdnjs.cloudflare.com/ajax/libs/mocha/2.2.5/mocha.css" rel="stylesheet" />
	</head>
	<body>
	<div id="mocha"></div>
	<script src="https://cdnjs.cloudflare.com/ajax/libs/mocha/2.2.5/mocha.js"></script>
	<script src="https://cdnjs.cloudflare.com/ajax/libs/chai/2.3.0/chai.js"></script>
	<script src="flatten.js"></script>
	<script src="test.flatten.js"></script>
	</body>
	</html>
	mocha.setup('bdd');
	const expect = chai.expect;

	describe('flatten()', function () {
	it('should flatten a simple nested object', function () {
	const source = {
	foo: {
	bar: 1
	}
	};

	const expected = {
	'foo.bar': 1
	};

	expect(flatten(source)).to.deep.equal(expected);
	});

	it('should flatten an object with nested arrays', function () {
	const source = {
	foo: [{
	bar: 1
	}, {
	bar: 2
	}]
	};

	const expected = {
	'foo.0.bar': 1,
	'foo.1.bar': 2
	};

	expect(flatten(source)).to.deep.equal(expected);
	});

	it('should flatten a complex nested object', function () {
	const source = {
	a: 1,
	b: {
	c: true,
	d: {
	e: 'foo'
	}
	},
	f: false,
	g: ['red', 'green', 'blue'],
	h: [{
	i: 2,
	j: 3
	}]
	};

	const expected = {
	'a': 1,
	'b.c': true,
	'b.d.e': 'foo',
	'f': false,
	'g.0': 'red',
	'g.1': 'green',
	'g.2': 'blue',
	'h.0.i': 2,
	'h.0.j': 3
	};

	expect(flatten(source)).to.deep.equal(expected);
	});

	it('should flatten an object with null values', function () {
	const source = {
	foo: {
	bar: null
	}
	};

	const expected = {
	'foo.bar': null
	};

	expect(flatten(source)).to.deep.equal(expected);
	});
	});

	mocha.run();