Converting array of objects into Object (v7)

Revision 7 of this benchmark created on

Description

https://stackoverflow.com/questions/19874555/how-do-i-convert-array-of-objects-into-one-object-in-javascript

And so we see, wrapping it into function that uses the simplest naive approach inside produces the fastest results (at least for now). Why? Probably because this func can be easily JIT-ted

Setup

let arr = [];
for (i = 0; i < 1000; i++) {
  arr[i] = {key: i, value: i+1}
}


function objarr2obj(ar, {key, value}) {
    const redfunc = (obj, item) => (obj[item[key]] = item[value], obj)
	return ar.reduce(redfunc, {})
}

function objarr2obj_naive(ar, {key, value}) {
    var res = {};		// maybe it'll be better not to imply constant-ness every time
    for (const obj of arr) {
        res[obj[key]] = obj[value]
    }
    return res
}

function objarr2obj_naive_const(ar, {key, value}) {
    const res = {};		// No it's not. const da king
    for (const obj of arr) {
        res[obj[key]] = obj[value]
    }
    return res
}

Teardown

Test runner

Ready to run.

Testing in
TestOps/sec
using Array.reduce
const objc = arr.reduce((obj, item) => { obj[item.key] = item.value; return obj} ,{});
ready
using Object.fromEntries
const objc = Object.fromEntries(arr.map(item => [item.key, item.value]));
ready
using Array.reduce shortened
const objc = arr.reduce((obj, item) => (obj[item.key] = item.value, obj), {});
ready
using Array.reduce shortened (wrapped into func)
const objc = objarr2obj(arr, {key: 'key', value: 'value'})
ready
using unpacking for
const objc = {};
for (const {key, value} of arr.values()) {
  objc[key] = value
}
ready
using unpacking for (wrapped into func)
const objc = objarr2obj_naive(arr, {key: 'key', value: 'value'})
ready
using unpacking for <const> (wrapped into func)
const objc = objarr2obj_naive_const(arr, {key: 'key', value: 'value'})
ready

Revisions

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