String concatenation: using += vs. using array push vs. unshift (v7)

Revision 7 of this benchmark created on

Description

Tests the performance difference of using two different ways of concatenating strings. The two TCs produce the same string result.

See http://jsperf.com/forloop-vs-reverse-while-loop-and-array-reverse/9 for array reverse vs custom loops.

See http://jsperf.com/array-push-reverse-vs-unshift-reverse for array push reverse vs. unshift reverse.

Preparation HTML

<script>
  var length = 1500;
  var html = [];
  var str = "";
</script>

Test runner

Ready to run.

Testing in
TestOps/sec
+=
str = "";
while (str.length < length) {
  str += '0';
}
ready
push
str = "";
while (html.length < length) {
  html.push('0');
}
str = html.join("");
ready
unshift
str = "";
while (html.length < length) {
  html.unshift('0');
}
str = html.join("");
ready
push reverse
str = "";
while (html.length < length) {
  html.push('0');
}
html.reverse();
str = html.join("");
ready
unshift reverse
str = "";
while (html.length < length) {
  html.unshift('0');
}
html.reverse();
str = html.join("");
ready
fast push
str = "";
while (html.length < length) {
  html[html.length] = "0";
}
str = html.join("");
ready
fast push reverse
str = "";
while (html.length < length) {
  html[html.length] = "0";
}
html.reverse();
str = html.join("");
ready

Revisions

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