let myString = "John Doe"; if (typeof myString === "string") { console.log("This variable is a string"); } else { console.log("This variable is not a string"); } Indeed, the myString is a string: This variable is a string Note: Even if the variable contains a number th...
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 is of string data type, it will...
JavaScript provides several ways to check if a variable is a string. One of the most common methods is to use the typeof operator, which returns the type of a variable. For example, the following code checks if a variable named “myVar” is a string: if (typeof myVar === "string")...
JavaScript offers many ways to check if a string contains a substring. Learn the canonical way, and also find out all the options you have, using plain JavaScript
In JavaScript, there are various methods available to check if a variable is undefined. Each method has its own use cases and subtle differences. 1. Using typeof Operator The typeof operator can be used to check if a variable is undefined by comparing its type with the string ‘undefined...
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 = "...
#Check if Variable Doesn't Equal Multiple Values in JavaScript To check if a variable is not equal to multiple values: Check if the variable is not equal to the values using the strict inequality (!==) operator. Use the logical AND (&&) operator to chain multiple conditions. ...
In JavaScript, includes() method checks whether a sub-string or a character is present in the string or not. It will return output in terms of true and false. This method is case sensitive, which means that it will consider uppercase and lowercase differently....
Topic: JavaScript / jQueryPrev|NextAnswer: Use the typeof operatorIf you want to check whether a variable has been initialized or defined (i.e. test whether a variable has been declared and assigned a value) you can use the typeof operator....
if (typeof v === "undefined") { // no variable "v" is defined in the current scope // *or* some variable v exists and has been assigned the value undefined } else { // some variable (global or local) "v" is defined in the current scope // *and* it contains a value other...