I'm trying to write a function on which if we pass the string like we do for split, it returns a string which is reversed -
This is what I've tried -
var abc = "hello"
var result;
String.prototype.reverser = function(str){
var temparr = str.split('').reverse().join('');
return temparr;
}
result = abc.reverser();
console.log(result);
I'm expecting olleh but rather getting -
VM1179:4 Uncaught TypeError: Cannot read property 'split' of undefined at String.reverser (:4:19) at :7:14
You don't need a parameter str. The string is already binded to the method on prototype. Just use this to access the string.
var abc = "hello"
var result;
String.prototype.reverser = function(){
return this.split('').reverse().join('');
}
result = abc.reverser();
console.log(result);Note: You shouldn't directly add enumerable properties to prototype. Instead use Object.defineProperty()
var abc = "hello";
Object.defineProperty(String.prototype,'reverser',{
value:function(){
return this.split('').reverse().join('');
}
})
var result = abc.reverser();
console.log(result)
Object.defineProperty rather than creating enumerable properties on built-in prototypes, which is a Bad Idea™. :-)
for-in loop on it. :-) People do very funny things...When extending String.prototype with your reverser() function, the string with the new method on it can be accessed with this; the way you have defined it expects an argument (str), that isn't provided. See how this can be used to access the string in this working snip:
var abc = "hello"
var anotherStr = "what do you know?"
var result;
var anotherResult;
String.prototype.reverser = function(){
var temparr = this.split('').reverse().join('');
return temparr;
};
result = abc.reverser();
anotherResult = anotherStr.reverser();
console.log(result);
console.log(anotherResult);
reverser.