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

ECMAScript 6 introduced String.prototype.includes:

const string = "foo";
const substring = "oo";

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

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includes doesn’t have Internet Explorer support, though. In ECMAScript 5 or older environments, use String.prototype.indexOf, which returns -1 when a substring cannot be found:

var string = "foo";
var substring = "oo";

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

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Also you can use search it is supported in all browsers String.prototype.seach

let string = "23 year old Web Developer";
console.log(string.search('Web') !== -1);
console.log(string.search(32) !== -1)

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