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How to check whether a string contains a substring in JavaScript?

How to check whether a string contains a substring in JavaScript?

In JavaScript, you have numerous options for determining whether a string contains a substring. Here are a few of the most prevalent approaches:

String.prototype.includes():

The includes() method determines whether a string contains a given substring and returns a boolean value (true or false).

const str = 'Hello, world!';
const substring = 'world';

if (str.includes(substring)) {
  console.log('Substring found.');
} else {
  console.log('Substring not found.');
}

String.prototype.indexOf(): 

The indexOf() method returns the first index in the string at which a substring can be found. If the substring cannot be retrieved, the function returns -1.

const str = 'Hello, world!';
const substring = 'world';

if (str.indexOf(substring) !== -1) {
  console.log('Substring found at index ' + str.indexOf(substring));
} else {
  console.log('Substring not found.');
}

String.prototype.search(): 

The search() method searches the string for a regular expression pattern and returns the index of the first match or -1 if none are found.

const str = 'Hello, world!';
const regex = /world/;

if (str.search(regex) !== -1) {
  console.log('Substring found at index ' + str.search(regex));
} else {
  console.log('Substring not found.');
}

Regular Expressions: 

Regular expressions can also be used to find substrings in a string. Regular expressions offer greater versatility, allowing you to match patterns and conduct more complicated searches.

const str = 'Hello, world!';
const regex = /world/;

if (regex.test(str)) {
  console.log('Substring found using regular expression.');
} else {
  console.log('Substring not found.');
}

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