added: Object.pick method

Author: GianlucaGuarini

objects.js

@@ -73,3 +73,15 @@ export function filter(source, filter) {
       )
     : source
 }
+
+/**
+ * Generate a new object picking only the properties from a given array
+ * @param {Object} source - target object
+ * @param {Array} keys - list of keys that we want to copy over to the new object
+ * @return {Object} a new object conaining only the keys that we have picked from the keys array list
+ */
+export function pick(source, keys) {
+  return isObject(source)
+    ? Object.fromEntries(keys.map((key) => [key, source[key]]))
+    : source
+}

objects.spec.js

@@ -4,6 +4,7 @@ import {
   defineProperties,
   defineProperty,
   filter,
+  pick,
 } from './objects.js'
 import { expect } from 'chai'
 
@@ -64,4 +65,16 @@ describe('Objects', function () {
   it('filter (null)', () => {
     expect(() => filter(null, (key) => key === 'name')).to.not.throw()
   })
+
+  it('pick', () => {
+    const source = { name: 'hello', class: 'test' }
+    const filtered = pick(source, ['name'])
+
+    expect(filtered.class).to.be.not.ok
+    expect(filtered.name).to.be.equal('hello')
+  })
+
+  it('pick (null)', () => {
+    expect(() => pick(null, ['name'])).to.not.throw()
+  })
 })