feat: add chunk util

CHANGELOG

@@ -1,3 +1,6 @@
+#1.21.0
+- feat: add chunk
+
 #1.20.0
 - feat: add transformKeysToSnake
 - feat: add sample

README.md

@@ -6,6 +6,7 @@ Currently supported utils:
 - `assignWith` - Assigns the object properties from the sources
 - `camelize` - simple camel case
 - `capitalize` - make first char uppercase
+- `chunk` - chunk an array into chunks
 - `clone` - Shallow clone the object
 - `cloneDeep` - deep clone functionality for objects
 - `difference` - creates an array of values from the first argument not included in the second argument

index.d.ts

@@ -1,6 +1,7 @@
 export function assignInWith (obj: Object, ...sources: Object[]): Object
 export function camelize (str: string): string
 export function capitalize (str: string): string
+export function chunk<T> (anArray: Array<T>, chunkSize: number): Array<Array<T>>
 export function clone (obj: Object): Object
 export function cloneDeep (obj: Object): Object
 export function difference (array: Array<any>, values: Array<any>): Array<any>

index.js

@@ -3,6 +3,7 @@
 const assignInWith = require('./src/assignWith')
 const camelize = require('./src/camelize')
 const capitalize = require('./src/capitalize')
+const chunk = require('./src/chunk')
 const clone = require('./src/clone')
 const cloneDeep = require('./src/cloneDeep')
 const difference = require('./src/difference')
@@ -56,6 +57,7 @@ module.exports = {
   assignInWith,
   camelize,
   capitalize,
+  chunk,
   clone,
   cloneDeep,
   difference,

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@bitfinexcom/lib-js-util-base",
-  "version": "1.20.0",
+  "version": "1.21.0",
   "description": "general utils",
   "main": "index.js",
   "scripts": {

src/chunk.js

@@ -0,0 +1,18 @@
+'use strict'
+
+const isNumber = require('./isNumber')
+
+const chunk = (anArray, chunkSize) => {
+  if (!Array.isArray(anArray) || !isInteger(chunkSize)) return []
+  const chunks = []
+  for (let i = 0; i < anArray.length; i += chunkSize) {
+    chunks.push(anArray.slice(i, i + chunkSize))
+  }
+  return chunks
+}
+
+const isInteger = (x) => {
+  return isNumber(x) && Math.trunc(x) === x
+}
+
+module.exports = chunk

test/chunk.js

@@ -0,0 +1,19 @@
+'use strict'
+
+/* eslint-env mocha */
+
+const assert = require('assert')
+const { chunk } = require('../index')
+
+describe('chunk', () => {
+  it('should chunk anArray in smaller arrays', () => {
+    assert.deepEqual(chunk([1, 2], 2), [[1, 2]])
+    assert.deepEqual(chunk([1, 2], 1), [[1], [2]])
+  })
+
+  it('should return empty array for invalid arguments', () => {
+    assert.deepEqual(chunk('notAnArray', 1), [])
+    assert.deepEqual(chunk([1, 2], 1.1), [])
+    assert.deepEqual(chunk([1, 2], 'notANumber'), [])
+  })
+})