Here you can find the source of includes(val, from)
String.prototype.includes = function(val, from) { return this.indexOf(val, from) !== -1; }
String.prototype.includes = function( other ){ return !!other && this.indexOf( other) != -1 function str_includes( that, other ){ return !!other && that.indexOf( other) != -1
String.prototype.includes = function () { 'use strict'; return String.prototype.indexOf.apply(this, arguments) !== -1; };
String.prototype.includes = function(matcher) { var includes = false; if( this.indexOf( matcher ) > 0 ) { includes = true; return includes;
String.prototype.includes = function (string, index) { if (typeof string === 'object' && string instanceof RegExp) throw new TypeError("First argument to String.prototype.includes must not be a regular expression"); return this.indexOf(string, index) !== -1; };
String.prototype.includes = function(substring){ return this.indexOf(substring) > -1 ? true : false;