In this article, we will check whether a string contains a specified substring or not. a substring is a portion of a string. It represents a sequence of characters extracted from a larger string. A substring can be as short as a single character or extend to multiple characters.
There are several approaches to checking whether a string contains a substring in JavaScript.
- Using includes() Method
- Using test() Method
- Using the match() method with a regular expression
- Using the indexOf() method
- Using the search() method with a regular expression
Approach 1: Using includes() Method:
The includes() method can be used to check whether a string contains a specified substring. It returns true if the substring is present. This method is case-sensitive.
Syntax:
string.includes(searchvalue, start)
Example: This example uses the includes() method of JavaScript to check for the substring in a string.
Javascript
let str = "Hello there! Welcome to neveropen";let flag = str.includes("Geeks");console.log(flag); |
true
Approach 2: Using test() Method:
In this method, we will use test() method to test the substring in the string. This method returns true if the substring found else return false.
Syntax:
/sub-string/.test( String );
Example: This example uses the test() method of JavaScript to check for the substring in a string.
Javascript
let str = "Hello there! Welcome to neveropen"; let flag = /neveropen/.test(str);console.log(flag); |
true
Approach 3 : Using the match() method with a regular expression:
In this approach, The match() method with a regular expression checks if a substring exists in the string, returning null if not found or an array of matches if found.
Syntax:
string.match(regExp)
Example: In this example, we are using the above-explained approach.
Javascript
let str = "Hello there! Welcome to neveropen";let substring = "there";let containsSubstring = str.match(new RegExp(substring)) !== null;console.log(containsSubstring); |
true
Approach 4: Using the indexOf() method
The indexOf() method returns the position of a substring in a string or -1 if not found, allowing us to check the substring’s existence.
Syntax:
str.indexOf(searchValue , index);
Example:
Javascript
let str = "Hello there! Welcome to neveropen";let substring = "neveropen";let result = str.includes(substring);console.log(result); |
true
Approach 5 : Using the search() method with a regular expression
In this approach, the search() method is called on the str string with a regular expression object created from the substring value using the new RegExp(substring). It searches for the first occurrence of the substring within the string. By checking if the result is not equal to -1, we determine if the substring exists in the string. The boolean result is stored in the containsSubstring variable and printed to the console.
Syntax:
string.search(new RegExp)
Example: In this example, we are using the above-explained approach.
Javascript
let str = "Hello there! Welcome to neveropen"let substring = "neveropen";let result = str.search(new RegExp(substring)) !== -1;console.log(result); |
true
