What is the javascript equivalent of the MongoDb sort function?

Question

I would like to create a Javascript function that works like the MongoDb sort function, for sorting object arrays. I am having trouble finding any documentation on how the MongoDB sort function works.

Example of a mongodb query and sort:

documentService.findAll().sort ({name: 1, height: -1})

I understand how "javascript sort" works. But I am interested in being able to replicate the MongoDb sort exactly. — Joshua Wright, Oct 17 '18 at 19:04
Here you go, have fun: https://github.com/mongodb/mongo/blob/master/src/mongo/db/sorter/sorter.cpp — Randy Casburn, Oct 17 '18 at 19:20

score 3 · Answer 1 · answered Oct 17 '18 at 19:23

Referencing my answer to Sort array of objects by string property value, a fairly compact implementation could look something like this:

const sortBy = fn => (a, b) => -(fn(a) < fn(b)) || +(fn(a) > fn(b))
const sort = o => Object.entries(o)
  .map(([k, sign]) => [sortBy(({ [k]: v }) => v), sign])
  .map(([f, sign]) => (a, b) => f(a, b) * sign)
  .reduce((f, g) => (a, b) => f(a, b) || g(a, b))

const mySort = sort({ name: 1, height: -1 })
const data = [{ name: 'b', height: 5 }, { name: 'a', height: 6 }, { name: 'a', height: 4 }, { name: 'b', height: 3 }]

console.log(data.sort(mySort))

What is the javascript equivalent of the MongoDb sort function?

1 Answers1