Nodejs String Starts With startsWith( pattern )

Method Source Code

// string utilities borrowed from Prototype JavaScript Library ( http://prototypejs.org/ )

// method startsWith
// 'Prototype Library'.startsWith( 'Pro' ); => true
String.prototype.startsWith = String.prototype.startsWith || function ( pattern ) {
    // We use `lastIndexOf` instead of `indexOf` to avoid tying execution
    // time to string length when string doesn't start with pattern.
    return this.lastIndexOf(pattern, 0) === 0;
}

Related

1. StartsWith( str )

   String.prototype.StartsWith = function( str )
       return this.indexOf( str ) == 0;
   };
   

2. starts( other )

   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
   

3. startsWith( str )

   String.prototype.startsWith = function( str ) {
       if ( str.length > this.length ) {
           return false;
       return( String( this ).substr( 0, str.length ) == str );
   };
   

4. startsWith( value )

   String.prototype.startsWith = function( value )
     return ( this.substr( 0, value.length ) == value ) ;
   

5. startsWith()

   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){
   ...
   

6. startsWith(e,t)

   String.prototype.startsWith||(String.prototype.startsWith=function(e,t){
        return t=t||0,this.substr(t,e.length)===e}
   );