strict-array-sort

Check for wrong comparators, returning boolean, in Array.sort

Usage no npm install needed!

<script type="module">
  import strictArraySort from 'https://cdn.skypack.dev/strict-array-sort';
</script>

README

strict-array-sort

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The problem

Many developers don't look up documentation quite enough, and sometimes think that comparator function in Array.sort should return boolean and implement sorting like this:

[1,3,2,4,5].sort((a,b)=>a>b);

returns

[ 1, 2, 3, 4, 5 ]

Sometimes it even works if you are lucky. But comparator function should return positive number, negative number or zero, otherwise sorting is broken:

[5, 8, 7, 1, 2, 3, 4, 6, 9, 10, 11, 12, 13].sort((a, b) => a > b)

returns

[ 4, 5, 3, 1, 2, 6, 7, 8, 9, 10, 11, 12, 13 ]

Also, there were changes in sorting in V8, and using booleans in comparators is broken even more than it was before.

[1,3,2,4,5].sort((a,b)=>a>b);

[ 1, 3, 2, 4, 5 ]

Solution

Of cause, you will have to fix your code. But to fix something, you need to find it at first, yeah? And sometimes you have a really large codebase to search in. That's when this module will help you. It has two modes:

Strict mode

All code which returns non numeric values from comparators will start throwing errors. To enable it, just install the module and initialize it like this:

const strictSort = require('strict-array-sort');
strictSort.apply();

Soft mode

If you don't want to throw errors, and want to just write logs, you can do it too:

const strictSort = require('strict-array-sort');
strictSort
  .apply((res, a, b)=>console.log(`Wrong sort result ${res} with args ${a} and ${b} on ${new Error().stack}`));

Warning

This module overrides Array.sort prototype to add check for comparator.

It is pretty dangerous and probably should not be used in production code.