EcmaScript 6 – String.prototype.repeat()

One simple function that is on the roster to be released in EcmaScript 6 is String.prototype.repeat. The following can be used to define it in browsers which don’t currently have it defined natively:

String.prototype.repeat = String.prototype.repeat || function(count) {
    return Array(count >= 0 ? parseInt(count, 10) + 1 : -1).join(this);
};

Here are some examples of using this function (modified from the originals found on MDN):

alert("->".repeat(-1));     // RangeError
alert("->".repeat(0));      // ""
alert("->".repeat(1));      // "->"
alert("->".repeat(2));      // "->->"
alert("->".repeat(3.6));    // "->->->" (count will be converted to integer)
alert("->".repeat(1/0));    // RangeError

There is more information about this new JavaScript function here.