Here you can find the source of startsWith( str )
String.prototype.startsWith = function( str ) { //w ww . j a v a2 s . com if ( str.length > this.length ) { return false; } return( String( this ).substr( 0, str.length ) == str ); };
String.prototype.StartsWith = function( str ) return this.indexOf( str ) == 0; };
String.prototype.starts = function( other ){ return !!other && other.substr( 0, this.length) == this function str_starts( that, other ){ return !!other && other.substr( 0, that.length) == that
String.prototype.startsWith = String.prototype.startsWith || function ( pattern ) { return this.lastIndexOf(pattern, 0) === 0;
String.prototype.startsWith = function( value ) return ( this.substr( 0, value.length ) == value ) ;
const strPro=String.prototype; String.prototype.startsWith||Object.assign(strPro,{ startsWith(searchString,position){ if (position) { return this.indexOf(searchString) === position; return this.indexOf(searchString)===0; }, endsWith(searchString,position){ ...
String.prototype.startsWith||(String.prototype.startsWith=function(e,t){ return t=t||0,this.substr(t,e.length)===e} );
String.prototype.startsWith = function (matchString) { if (this == matchString) return true; var matchString = '^' + matchString + '[\x20-\x7E]+$'; var regex = new RegExp(matchString); return !!this.match(regex); };