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

回答1

CMAScript6 introduced String.prototype.includes:

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

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

includes doesn’t have InternetExplorer support, though. In ECMAScript5 or older environments, use

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

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

評論：

While this is a good answer, and the OP never requested for a "case-sensitive" search, it should be noted that includes

回答2

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 with no or incomplete ES6 support. To make it work in old browsers, you may wish to use a transpiler like

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;
    }
  };
}