squint/core Shuffle function suggestions

[kigiri]

squint/src/squint/core.js

Lines 1851 to 1855 in 6d6e3fc

	export function shuffle(coll) {
	return [...coll].sort(function (_a, _b) {
	return Math.random() - 0.5;
	});
	}

This is not a good way to shuffle, distribution is biased, and it's not efficient.

function shuffle(coll) {
  const result = [...coll]
  let left = coll.length
  while (left) {
    const i = Math.floor(Math.random() * left--)
    const tmp = result[left]
    result[left] = result[i]
    result[i] = tmp
  }

  return result
}

Here an example of the distribution in chrome:

You can read more about why this isn't a recommanded method here:
https://stackoverflow.com/questions/962802/is-it-correct-to-use-javascript-array-sort-method-for-shuffling

And here, clicking on the solution for straitforward examples: https://javascript.info/task/shuffle

[borkdude]

Thanks!

[borkdude]

The source code you list after the squint link, is that a recommendation of how to do it, or not?
It seems fairly close to how goog.array is doing it: https://github.com/google/closure-library/blob/master/closure/goog/array/array.js#L1741
If so, PR welcome