How to verify that a string has a substring in JavaScript?
Asked by Sohail · · 2155 views
Is there any method to check if string has a substring something like String.contains('some string')
.
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2 Answers
In ECMAScript 6 has String.prototype.includes
:
const string = "foo";
const substring = "oo";
console.log(string.includes(substring));
Old browsers do not support includes
. So for old browsers use String.prototype.indexOf
that returns -1
if a substring not found:
var string = "foo";
var substring = "oo";
console.log(string.indexOf(substring) !== -1);
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There is a String.prototype.includes
in ES6:
"potato".includes("to");
> true
Note that this does not work in Internet Explorer or some other old browsers. To make it work in old browsers use following snippet:
if (!String.prototype.includes) {
String.prototype.includes = function(search, start) {
'use strict';
if (typeof start !== 'number') {
start = 0;
}
if (start + search.length > this.length) {
return false;
} else {
return this.indexOf(search, start) !== -1;
}
};
}
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