Performance test for assign vs reduce

assign_vs_reduce.js

const randString = () => Math.random().toString(36).substring(7);

const gen = (n) =>
  new Array(n).fill(1).map(() => ({key: randString(), value: Math.random()}));

const array1 = gen(100);
const array2 = gen(1000);
const array3 = gen(100000);

const assign = (arr) =>
  Object.assign(
    {},
    ...(arr.map(({key, value}) => ({[key]: value}))),
  );

const reduce = (arr) =>
  arr.reduce((acc, {key, value}) => ({...acc, [key]: value}), {});


function perf(label, arr, func) {
  t0 = performance.now();
  func(arr);
  t1 = performance.now();
  console.log(`${label} took ${t1 - t0} ms to finish`)
}

perf('100 assign', array1, assign);
perf('100 reduce', array1, reduce);

perf('1000 assign', array2, assign);
perf('1000 reduce', array2, reduce);

perf('10000 assign', array3, assign);
perf('10000 reduce', array3, reduce);