Javascript Useful Object Methods

Useful Object Methods

Objects and Arrays by default are mutable in javascript. Objects in Javascript is a collection of key:value pairs. It can also consist of methods as properties along with other data types.

Below are most used Object methods in javascript in real time applications.

Object.assign()

This method copies values from one or more object(s) to another and returns the modified target object.

const target = { a: 1, b: 2 };
const source = { b: 4, c: 5 };
const result = Object.assign(target, source)

Object.is()

This method compares whether two values are same and returns a boolean based on the comparison.

Object.is is not equivalent to === operator. === treats +0 and -0 as equal and NaN as not equal whereas Object.is doesn’t.

Object.is(5 , 5) // true
Object.is("true" , "true") // true
Object.is(2 , 5) // false
Object.is("false" , "true") // false
Object.is([], []) // false
const obj1 = { a: 1 };
const obj2 = { a: 1 };
Object.is(obj1, obj1) // true
Object.is(obj1, obj2) // false

Object.entries()

This method converts objects key:value pair into array sets

const obj = { a: 1, b: 2 };
Object.entries(obj) // [ [ 'a', 1 ], [ 'b', 2 ] ]

Object.fromEntries()

This method converts array sets into objects key:value pairs

const obj = [ [ 'a', 1 ], [ 'b', 2 ] ]
Object.fromEntries(obj) // { a: 1, b: 2 }

Object.keys()

This method creates an array containing keys of an object

const obj = { a: 1, b: 2 }
Object.keys(obj) // [ 'a', 'b' ]

Object.values()

This method creates an array containing values of an object

const obj = { a: 1, b: 2 }
Object.values(obj) // [ 1, 2 ]