How to check variable is Array or Object in JavaScript?

Here you will learn how to check whether a variable is a type of Array or an Object in JavaScript.

In the following example, you can see there are three variables (var1, var2, var3) containing three different types of values. But the result shows that all three values are object types –

const var1 = {};
const var2 = [];
const var3 = null;

console.log(typeof var1);
console.log(typeof var2);
console.log(typeof var3);

/* Result is -
object
object
object
*/

How to get the exact type of a value in JS?

JS condition to check if the variable is Array or Object

const val = {name:"John"}

// For Object
if (val !== null && typeof val === "object" && val.constructor === Object) {
    // Code will Execute if the value is Object
}

// For Array
if (typeof val === "object" && Array.isArray(val)) {
    // Code will Execute if the value is Array
}

Wrapping the logic into the function

const var1 = {};
const var2 = [];

// Checking if value is Object
function isObject(val) {
    return (
        val !== null && typeof val === "object" && val.constructor === Object
    );
}

// Checking if value is Array
function isArray(val) {
    return typeof val === "object" && Array.isArray(val);
}

if (isObject(var1)) {
    console.log("This is an Object.");
}

if (isArray(var1)) {
    console.log("This is an Array.");
}