feat(initArray): init array with length and prefilled value (#82)

Closes (#81)

Author: syonip

src/index.js

@@ -1,4 +1,5 @@
 
+import initArray from './init-array'
 import reduce from './reduce-to-tally'
 import flatten from './flatten'
 import getQueryStringParam from './get-query-string-param'
@@ -26,6 +27,7 @@ import dec2bin from './dec2bin'
 import searchAndReplace from './search-and-replace'
 
 export {
+  initArray,
   reduce,
   flatten,
   snakeToCamel,

src/init-array.js

@@ -0,0 +1,15 @@
+export default initArray
+
+/**
+ * Original Source:
+ * http://stackoverflow.com/questions/1295584/most-efficient-way-to-create-a-zero-filled-javascript-array
+ *
+ * This method will return an array with the given length, prefilled with given value
+ *
+ * @param {Number} len - the length of the array
+ * @param {*} value - The value to prefill
+ * @return {Array} - The prefilled array
+ */
+function initArray(len, value) {
+  return new Array(len).fill(value)
+}

test/init-array.test.js

@@ -0,0 +1,23 @@
+import test from 'ava'
+import {initArray} from '../src'
+
+test('inits an array with numbers', t => {
+  const expected = [7, 7, 7, 7]
+  const actual = initArray(4, 7)
+  t.deepEqual(actual, expected)
+})
+
+test('inits an array with a string', t => {
+  const expected = ['pepo', 'pepo', 'pepo', 'pepo']
+  const actual = initArray(4, 'pepo')
+  t.deepEqual(actual, expected)
+})
+
+test('fills an array with a boolean', t => {
+  const expected = [false, false, false, false]
+  const actual = initArray(4, false)
+  t.deepEqual(actual, expected)
+})
+
+test.todo('allow for non-primitive values like objects, arrays, and dates')
+