TypeScript String includes() Method

TypeScript includes() a predefined string method that comes from JavaScript. It checks if a given string contains any specified substring or not based on this it returns a boolean value.

Syntax

string.includes(searchValue, fromIndex?: number): boolean;

Parameters:

• searchValue: Here you have to pass the substring that you want to find out within the string.
• fromIndex (Optional): The starting point, for the search. By default, it begins at 0 indicating that the search commences, from the start of the string.

Return Value:

If the given searchValue is found within the string it returns true otherwise it returns false.

Example 1: In this example, we are checking for substring presence.

Javascript

let str: string = "Welcome to GFG";
let hasString: boolean = str
    .includes("GFG");
console.log(hasString);

Output:

true

Example 2: In this example we are demonstrating case sensitivity.

Javascript

let str: string = "TypeScript";
let check1: boolean = str
    .includes("Typescript");
let check2: boolean = str
    .includes("TypeScript");

console.log(check1);
console.log(check2);

Output:

false
true