LANGUAGE » JAVASCRIPT

Object

Last updated:
Reference:developer.mozilla.org

Basic ​

js
const animal = 'seagull'
const obj = {
   'cat' : 'Meow',
   'dog' : 'Bark'
   [animal]: 'Mew',
}
obj.cat === obj['cat']
delete obj.cat  // delete key
for (let key in obj) {}

Calls from Object class ​

MethodDescription
Object.prototype.hasOwnProperty.call(obj, key)
Object.hasOwn(object, key)		Return true if object owns property, false otherwise.
Object.assign(target, source)Copy all own properties from source to target.
Object.keys(obj)Return an array of keys.
Object.values(obj)Return an array of values.
Object.entries(obj)Return an array of key-value pairs.

Looping object keys ​

js
Object.entries(object1).forEach(([key, value]) => {
  console.log(`${key}: ${value}`);
})

Object.keys(obj).forEach(function (key) {})

Shallow and deep object copy ​

js
// Shallow
Object.assign({}, obj)

// Deep
JSON.parse(JSON.stringify(obj))

let $ = require('jquery')
$.extend(true, {}, oldObject)

let _ = require('lodash')
_.clonedeep(original)