feat(objectValuesToString): add 'objectValuesToString' method with tests

To close #33: I've added a function that takes in parameter an object and returns a comma-separated

string that is composed of all its values. The tests make sure the value passed is really an object

and that its undefined or null properties are skipped

Closes #33 
Ref #35

Author: DdZ-Fred

src/index.js

@@ -5,6 +5,8 @@ import padLeft from './pad-left'
 import randomInteger from './random-integer'
 import arrayFill from './array-fill'
 import sortObjectsArray from './sort-objects-array'
+import objectValuesToString from './object-values-to-string'
+
 
 export {
   flatten,
@@ -14,4 +16,5 @@ export {
   randomInteger,
   arrayFill,
   sortObjectsArray,
+  objectValuesToString,
 }

src/object-values-to-string.js

@@ -0,0 +1,22 @@
+export default objectValuesToString
+
+/**
+ * Original Source: http://stackoverflow.com/a/31017540
+ *
+ * This method will take an object in parameter and return a
+ * comma-separated String composed of all its properties' values
+ *
+ * @param  {Object} obj - The object from which the values are taken
+ * @return {String} A comma-separated String that contains all the object values
+ */
+function objectValuesToString(obj) {
+  if (!obj) {
+    return ''
+  } else if (typeof obj !== 'object' || obj instanceof Date) {
+    return ''
+  }
+
+  return Object.keys(obj).map(key => obj[key])
+    .filter(val => val || val === 0 || val === '0' || val === false)
+    .join(', ')
+}

test/object-values-to-string.test.js

@@ -0,0 +1,116 @@
+import test from 'ava'
+import {objectValuesToString} from '../src'
+
+test('returns a comma-separated string with all the object values', t => {
+  const object = {
+    id: 187,
+    title: 'egghead.io is awesome',
+    subtitle: 'Contribute on GitHub',
+    author: 'Patata Patati',
+  }
+  const expected = '187, egghead.io is awesome, Contribute on GitHub, Patata Patati'
+  const actual = objectValuesToString(object)
+  t.deepEqual(actual, expected)
+})
+
+test('returns an empty string if value in param is falsy: false', t => {
+  const object = false
+  const expected = ''
+  const actual = objectValuesToString(object)
+  t.deepEqual(actual, expected)
+})
+
+test('returns an empty string if value in param is falsy: zero(Number)', t => {
+  const object = 0
+  const expected = ''
+  const actual = objectValuesToString(object)
+  t.deepEqual(actual, expected)
+})
+
+test('returns an empty string if value in param is falsy: zero(String)', t => {
+  const object = '0'
+  const expected = ''
+  const actual = objectValuesToString(object)
+  t.deepEqual(actual, expected)
+})
+
+test('returns an empty string if value in param is falsy: empty string', t => {
+  const object = ''
+  const expected = ''
+  const actual = objectValuesToString(object)
+  t.deepEqual(actual, expected)
+})
+
+test('returns an empty string if value in param is falsy: null', t => {
+  const object = null
+  const expected = ''
+  const actual = objectValuesToString(object)
+  t.deepEqual(actual, expected)
+})
+
+test('returns an empty string if value in param is falsy: undefined', t => {
+  const object = undefined
+  const expected = ''
+  const actual = objectValuesToString(object)
+  t.deepEqual(actual, expected)
+})
+
+test('returns an empty string if value in param is falsy: NaN', t => {
+  const object = NaN
+  const expected = ''
+  const actual = objectValuesToString(object)
+  t.deepEqual(actual, expected)
+})
+
+test('returns an empty string if value in param is not an object: function', t => {
+  function object() {
+    return 'JavaScript, ES6, Github!'
+  }
+  const expected = ''
+  const actual = objectValuesToString(object)
+  t.deepEqual(actual, expected)
+})
+
+test('returns an empty string if value in param is not an object: number', t => {
+  const object = 878565
+  const expected = ''
+  const actual = objectValuesToString(object)
+  t.deepEqual(actual, expected)
+})
+
+test('returns an empty string if value in param is not an object: string', t => {
+  const object = 'This is a string'
+  const expected = ''
+  const actual = objectValuesToString(object)
+  t.deepEqual(actual, expected)
+})
+
+test('returns an empty string if value in param is not an object: boolean', t => {
+  const object = true
+  const expected = ''
+  const actual = objectValuesToString(object)
+  t.deepEqual(actual, expected)
+})
+
+test('returns an empty string if value in param is a Date', t => {
+  const object = new Date()
+  const expected = ''
+  const actual = objectValuesToString(object)
+  t.deepEqual(actual, expected)
+})
+
+test('skips falsy object values excluding zero and false', t => {
+  const object = {
+    id: 0,
+    position: '0',
+    title: undefined,
+    subtitle: 'JavaScript is magic',
+    author: null,
+    error: NaN,
+    visible: false,
+    otherProp: '',
+  }
+  const expected = '0, 0, JavaScript is magic, false'
+  const actual = objectValuesToString(object)
+  t.deepEqual(actual, expected)
+})