what is the different between (myVar && { myVar }) and { myVar }

September 4, 2022

I have seen few JavaScript repositories online where an object is created in the following syntax

const myVar

const myObj = (myVar && {myVar})

I’m wondering why do we need to use this syntax, when the same output can be acheived by simply declaring the object like this:

const myObj = {myVar}

Is there any difference between those two?

>Solution :

The version with && only creates the object if the value of myVar isn’t falsey.

Compare these examples:

let myVar1 = 10;
let myObj1_and = (myVar1 && {myVar1});
let myObj1_noand = {myVar1};
console.log(myObj1_and);
console.log(myObj1_noand);

let myVar2 = null;
let myObj2_and = (myVar2 && {myVar2});
let myObj2_noand = {myVar2};
console.log(myObj2_and);
console.log(myObj2_noand);

Without the &&, it creates the object regardless of the value of the variable.