How to Check Whether a String Contains a Substring in JavaScript

As a software developer, checking if a string contains a substring is a common task.

In JavaScript, there are several ways to achieve this.

In this article, we’ll explore various methods to check if a string contains a substring in JavaScript.

Method 1: Using the includes() method

The simplest and most straightforward way to check if a string contains a substring is to use the includes() method.

The includes() method returns a Boolean value indicating whether the string contains the substring.

Example:

let string = "Hello World";
let substring = "Hello";

console.log(string.includes(substring)); // returns true

Method 2: Using the indexOf() method

The indexOf() method returns the index of the first occurrence of the substring in the string.

If the substring is not present, the method returns -1. We can use this information to check if the string contains the substring.

Example:

let string = "Hello World";
let substring = "Hello";

if (string.indexOf(substring) !== -1) {
console.log("Substring is present");
} else {
console.log("Substring is not present");
}

Method 3: Using the search() method

The search() method is similar to the indexOf() method, but it also accepts regular expressions as an argument.

Example:

let string = "Hello World";
let substring = "Hello";

if (string.search(substring) !== -1) {
console.log("Substring is present");
} else {
console.log("Substring is not present");
}

Method 4: Using the RegExp() object

We can also use the RegExp() object to check if a string contains a substring.

The RegExp() object is used to create a regular expression pattern.

We can then use the test() method to check if the string contains the substring.

Example:

let string = "Hello World";
let substring = "Hello";

let regex = new RegExp(substring);

if (regex.test(string)) {
console.log("Substring is present");
} else {
console.log("Substring is not present");
}