string concat vs array join (v8)

Revision 8 of this benchmark created on

Setup

var words = ['this', 'is', 'a', 'test'];
  
  var text = words[0];
  
  var a = [words[0]];
  var b = [];
  var i;
  
  var text2;

Test runner

Ready to run.

Testing in
TestOps/sec
Concat
for(i = 1; i < 10000; ++i)
{
    text += ' ' + words[i & 3] + Math.random();
}

text2 = text;
ready
Join
for(i = 1; i < 10000; ++i)
{
    a.push(' ',words[i & 3],Math.random());
}

text2 = a.join('');
ready
Join without push()
for(i = 1; i < 10000; ++i)
{
    a[i] = ' ' + words[i & 3] + Math.random();
}

text2 = a.join('');
ready
Join without space concat
for(i = 1; i < 10000; ++i)
{
    a[i] = words[i & 3] + Math.random();
}

text2 = a.join(' ');
ready
Join without concat
for(i = 1; i < 20000; ++i)
{
    a[i] = words[i & 3]
    a[++i] = Math.random();
}

text2 = a.join(' ');
ready

Revisions

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