joaolucasl/proposal-array-prototype-partition

A TC39 proposal for an utility function that returns two arrays based on the items' conformity to a predicate.

proposal-array-prototype-partition's Issues

Consider `groupBy` generic operation

It's a bit more generic operation "partition"

let groupBy = (f, coll) => {
  let rf = (acc, el) => {
    let id = f(el);
    acc[id] = [... (acc[id] || []), el]
    return acc
  }
  return coll.reduce(rf , {})
}

Can be used as partition as:

let {false: f, true: t} = groupBy( x => x == 2 , [1,2,3])

Maybe should we accumulate over an actual Map allowing f return any object (?!)