Nodejs String Starts With startsWith(substring)

Method Source Code

"use strict";//from   www.j a v  a  2  s.  c  o m

String.prototype.startsWith  = function(substring) {
    var substringLength = substring.length;

    if (substringLength > this.length) {
        return false;
    }
    var i;
    for (i = 0; i < substringLength; i += 1) {
        if (substring[i] !== this[i]) {
            return false;
        }
    }

    return true;
};

Related

1. startsWith(string)

   String.prototype.startsWith = function(string){
     if (typeof(string) !== "string") {
       throw new Error("Input argument was not a string");
     } else if (this.substring(0, string.length) === string) {
       return true;
     } else {
       return false;
   };
   ...
   

2. startsWith(string)

   String.prototype.startsWith = function (string){
     return this.indexOf(string) === 0;
   };
   

3. startsWith(substr)

   String.prototype.startsWith = function(substr) {
       for (var i = 0; i < substr.length; i++) {
           if (this[i] !== substr[i]) {
               return false;
       return true;
   

4. startsWith(substr)

   String.prototype.startsWith = function(substr) {
     return (this.indexOf(substr) == 0);
   };
   

5. startsWith(substring)

   String.prototype.startsWith = function (substring) {
       var stringCut = this.substring(0, substring.length);
       return stringCut === substring;
   

6. startsWith(substring)

   String.prototype.startsWith = function(substring) {
       var compareString = this.substring(0, substring.length);
       return compareString === substring;
   };
   

7. startsWith(suffix)

   String.prototype.startsWith = function(prefix) {
     return (this.indexOf(prefix) == 0);
   };
   module.exports = {};
   

8. startsWith(suffix)

   String.prototype.startsWith = function (suffix) {
       return !(this.indexOf(suffix) !== 0);
   };
   

9. startsWith(text)

   console.log(typeof Array.prototype.sort);          
   console.log(typeof String.prototype.substring);    
   String.prototype.startsWith = function (text) {
     return this.indexOf(text) === 0;
   };
   var msg = 'Hello world!';
   console.log(msg.startsWith('Hello'));