Javascript Experiment to test unique arrays

[Arlen22]

Here is a test you can run in your browser console to see which method of getting a unique array of strings is the fastest. I was surprised. Turns out an object of true values is much much faster than indexOf.

for (let r = 1; r < 10; r++) {
  let test = Math.random().toExponential(10);
  let count = 1000 * r;
  let test1 = {};
  let test2 = [];
  console.time(r + " test 1");
  for (let i = 0; i < count; i++) {
    let item = test + "" + i;
    if (!test1[item]) test1[item] = true;
  }
  console.timeEnd(r + " test 1");
  console.time(r + " test 2");
  for (let i = 0; i < count; i++) {
    let item = test + "" + i;
    if (test2.indexOf(item) === -1) test2.push(item);
  }
  console.timeEnd(r + " test 2");
}

[Arlen22]

Here are my results

1 test 1: 0.869140625 ms
1 test 2: 26.635986328125 ms
2 test 1: 1.674072265625 ms
2 test 2: 59.73095703125 ms
3 test 1: 2.68798828125 ms
3 test 2: 156.031982421875 ms
4 test 1: 3.43798828125 ms
4 test 2: 294.0849609375 ms
5 test 1: 3.31201171875 ms
5 test 2: 522.2490234375 ms
6 test 1: 4.83203125 ms
6 test 2: 764.8798828125 ms
7 test 1: 4.816162109375 ms
7 test 2: 1109.547119140625 ms
8 test 1: 6.426025390625 ms
8 test 2: 1539.6611328125 ms
9 test 1: 6.79296875 ms
9 test 2: 2001.7919921875 ms

[pmario]

hmmm. There may be reason, why the TW wiki-store is an object ;)

[Jermolene]

Hi @Arlen22 I think this is to be expected, are there specific instances of indexOf that need reviewing?

[Arlen22]

It was a surprise to me. If it was already known, then that's great. I believe the tag operator may have used that last time I was in there, but I'm probably going to audit this at some point and make a PR if I find anything.