Is there a splice method for strings?

Question

The Javascript splice only works with arrays. Is there similar method for strings? Or should I create my own custom function?

The substr(),

Answer 1

I would like to offer a simpler alternative to both the Kumar/Cody and the Louis methods. On all the tests I ran, it performs as fast as the Louis method (see fiddle tests for benchmarks).

String.prototype.splice = function(startIndex,length,insertString){
    return this.substring(0,startIndex) + insertString + this.substring(startIndex + length);
};

You can use it like this:

var creditCardNumber = "5500000000000004";
var cardSuffix = creditCardNumber.splice(0,12,'****');
console.log(cardSuffix);  // output: ****0004

See Test Results: https://jsfiddle.net/0quz9q9m/5/