How Can I Efficiently Check for Substring Presence in JavaScript?

Checking Substring Presence in JavaScript

The absence of a dedicated "String.contains()" method in JavaScript may raise questions for developers. This article explores a practical approach to checking whether a string contains a substring.

Checking Substring Presence

Despite the lack of a dedicated method, JavaScript provides an array of methods that can be leveraged to check substring presence. One such approach involves using the " indexOf()" method:

const string = "Hello, world!"
const substring = "world";

console.log(string.indexOf(substring) !== -1); // true

In this example, the "indexOf()" method searches for the specified substring within the string. If the substring is found, the method returns its index in the string. Otherwise, it returns -1. Checking the result with a comparison to -1 allows us to determine whether the substring is present or not.

Furthermore, ES6 introduces an alternative approach using the "includes()" method. This method is more concise and is supported by most modern browsers:

const string = "Hello, world!"
const substring = "world";

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

The "includes()" method takes a substring as an argument and returns a boolean value indicating whether the substring is present within the string.

Ultimately, the choice of method depends on the preferences and compatibility requirements of the project. Both "indexOf()" and "includes()" offer effective ways to check for substring presence in JavaScript.

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