benchmarking arr.find vs. dict lookup

benchark-arr-find.js

const Benchmark = require("benchmark");
const { ObjectId } = require("bson");
const _ = require("lodash");
const casual = require("casual")

const size = 1000;
let array = new Array(size).fill(0).map(() => new ObjectId().toHexString());

const docs = array.map((_id) => ({
    _id,
    firstName: casual.name,
    lastName: casual.name,
    email: casual.email,
}));
const keyedDocs = _.keyBy(docs, "_id")
const keysToGet = _.shuffle(array);

const suite = new Benchmark.Suite();
function doNothing() { }

suite
    .add("object access", function () {
        let result = keysToGet.map((_id) => keyedDocs[_id]);
        doNothing(result)
    })
    .add("array", function () {
        let result = []
        for (const key of keysToGet) {
            result.push(docs.find((doc) => doc._id === key));
        }
        doNothing(result)
    })
    .on("cycle", (event) => {
        console.log(`\t ${size}`, String(event.target));
    })
    .on("complete", function () {
        console.log(
            `Fastest for ${size} is ` +
            this.filter("fastest").map("name")
        );
        console.log("\n\n");
    })
    .run({ async: false });