JavaScript String Repetition Algorithm

JavaScript performance comparison

Revision 6 of this test case created


Test cases for string repetition.

Preparation code

<script src=""></script>
A string of the indicated string length will be replicated.
Benchmark.prototype.setup = function() {
    function stringFill3(x, n) {
        var s = '';
        for (;;) {
            if (n & 1) s += x;
            n >>= 1;
            if (n) x += x;
            else break;
        return s;
    stringValue = 'a';
    stringRepeats = 100000;
    function repeat(x, num )
        return new Array( num + 1 ).join( x);
    function repeat2(x, count) {
        var result = '', pattern = ['', x, x=x+x];
        while (count > 0) {
            result += pattern[count&1]+pattern [count&2];
            count >>=2 , pattern[1]=x=x+x,pattern[2]=x=x+x;
        return result;
    function repeat3(x, n) { return x.repeat(n); }

Preparation code output

A string of the indicated string length will be replicated.

Test runner

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Testing in unknown unknown
Test Ops/sec
Original Algorithm by Joseph Myers
stringFill3(stringValue, stringRepeats);
Accepted Answer on Stack Overflow
repeat(stringValue, stringRepeats);
A degraded version of my solution
repeat2(stringValue, stringRepeats);

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