To check if a variable is an array in Javascript is essential to handle data appropriately. We will discuss three different approaches to check if a variable is an array or not. We are having an array and a string, and our task is to check if a variable is an array in JavaScript. ...
If you try to access an element of an array that hasn’t been initialized, it returns undefined. Here’s an example of the code. let numbers = [1, 2]; console.log(numbers[3]); // undefined Read More: Common JavaScript Issues and its Solutions Methods to check if a Variable is Un...
Checks if value is classified as an Array object. constarray=['🍝','🍜','🍲'];constnotArray='not array';_.isArray(array);// true_.isArray(notArray);// false Underscore Returns true if object is an Array. constarray=['🍝','🍜','🍲'];constnotArray='not array';_.isArr...
There are several ways of checking if an variable is an array or not. The best solution is the one you have chosen. variable.constructor === Array 1. This is the fastest method on Chrome, and most likely all other browsers. All arrays are objects, so checking the constructor property is...
If the comparison evaluates to true, then the variable is an array otherwise, it is not. const myArr = [1, 2, 3]; const myObj = {name: "John"}; myArr instanceOf Array; // output: true myObj instanceOf Array; // output: false JavaScript Copy By comparing the prototype of the ...
If the variable is not defined, typeof will return the string “undefined”. Here’s how you can use it: let myVar; if (typeof myVar === "undefined") { console.log("myVar is undefined"); } else { console.log("myVar is defined"); } Output: myVar is undefined In this example...
There are several ways of checking if an variable is an array or not. The best solution is the one you have chosen. variable.constructor === Array This is the fastest method on Chrome, and most likely all other browsers. All arrays are objects, so checking the constructor property is a...
str2 = 'That is your place.' str3 = new String('Great Place'); Now to check whether a given variable is a string or not, we'll use a JavaScript operator calledtypeof. Syntax: typeof variable; This operator returns the data type of the variable specified after it. If the variable ...
JavaScript Define a Function to Check If a Variable is a String 6 7 8 9 // Defining a function 10 function isString(myVar) { 11 return (typeof myVar === 'string'); 12 } 13 14 // Sample variables 15 var x = 10; 16 var y = true; 17 var z = "...
Javascript Boolean Type Introduction Using the typeof operator, we can check the datatype of a variable. If the variable is a Boolean value, typeof will return the string 'boolean'. Copy vara =Boolean(true);varb = false;//www.java2s.comvarc ="";vard = newDate();if(typeofa ==='...