Repeat String - Javascript

Question

What is the best or most concise method for returning a string repeated an arbitrary amount of times?

The following is my best shot so far:

function repeat(s, n){
    var a = [];
    while(a.length < n){
        a.push(s);
    }
    return a.join('');
}

Answer 1

Why not just build a string with s n times?

Answer 2

function repeat(s, n) { var r=""; for (var a=0;a<n;a++) r+=s; return r;}

Answer 3

I'd put this function onto the String object directly. Instead of creating an array, filling it, and joining it with an empty char, just create an array of the proper length, and join it with your desired string. Same result, less process!

String.prototype.repeat = function( num )
{
    return new Array( num + 1 ).join( this );
}

alert( "string to repeat\n".repeat( 4 ) );

Answer 4

/**
@desc: repeat string
@param: n - times
@param: d - delimiter
*/

String.prototype.repeat = function (n, d){
   return --n
     ? this+d+this.repeat(n,d)
     : ''+this
}

this is how to repeat string several times using delimeter.

Answer 5

Expanding P.Bailey's solution:

String.prototype.repeat = function(num) {
    return new Array(isNaN(num)? 1 : ++num).join(this);
    }

This way you should be safe from unexpected argument types:

var foo = 'bar';
alert(foo.repeat(3));              // Will work, "barbarbar"
alert(foo.repeat('3'));            // Same as above
alert(foo.repeat(true));           // Same as foo.repeat(1)

alert(foo.repeat(0));              // This and all the following return an empty
alert(foo.repeat(false));          // string while not causing an exception
alert(foo.repeat(null));
alert(foo.repeat(undefined));
alert(foo.repeat({}));             // Object
alert(foo.repeat(function () {})); // Function

EDIT: Credits to jerone for his elegant ++num idea!

Answer 6

Or use prototypejs http://api.prototypejs.org/language/string.html#times-instance_method