[JavaScript] Benchmark Accessing Performance among Array, Object, Map. (Run in browser or node)

bench-array-map-object-int-key.js

const OBJ = {};
const ARR = [];
const MAP = new Map();
const KEYS = [];
LENGTH = 100000;
for (let i=0; i<LENGTH; i++) {
    const key =  i;   // Use int as key
    const val = { name: 'foo', id: Math.random(), count: 0 };
    KEYS.push(key);
    OBJ[key] = val;
    MAP.set(key, val);
    ARR[i] = val;
}

function dummy(val) {
    val.count += 1;
}

const RAND_I = [];
const RAND_KEYS = [];
while (RAND_I.length <= LENGTH) {
    const i = Math.round(Math.random() * (LENGTH-1));
    RAND_I.push(i);
    RAND_KEYS.push(KEYS[i]);
}

console.log('==============')
console.log('int as keys')
console.log('==============')
console.time('Array')
for (const i of RAND_I) {
    dummy(ARR[i]);
}
console.timeEnd('Array')

console.time('Map')
for (const k of RAND_KEYS) {
    dummy(MAP.get(k));
}
console.timeEnd('Map')

console.time('Object')
for (const k of RAND_KEYS) {
    dummy(OBJ[k]);
}
console.timeEnd('Object')

bench-array-map-object-string-key.js

const OBJ = {};
const ARR = [];
const MAP = new Map();
const KEYS = [];
LENGTH = 100000;
for (let i=0; i<LENGTH; i++) {
    const key = 'k' + i;   // Use string as key
    const val = { name: 'foo', id: Math.random(), count: 0 };
    KEYS.push(key);
    OBJ[key] = val;
    MAP.set(key, val);
    ARR[i] = val;
}

function dummy(val) {
    val.count += 1;
}

const RAND_I = [];
const RAND_KEYS = [];
while (RAND_I.length <= LENGTH) {
    const i = Math.round(Math.random() * (LENGTH-1));
    RAND_I.push(i);
    RAND_KEYS.push(KEYS[i]);
}

console.log('==============')
console.log('string as keys')
console.log('==============')

console.time('Array')
for (const i of RAND_I) {
    dummy(ARR[i]);
}
console.timeEnd('Array')

console.time('Map')
for (const k of RAND_KEYS) {
    dummy(MAP.get(k));
}
console.timeEnd('Map')

console.time('Object')
for (const k of RAND_KEYS) {
    dummy(OBJ[k]);
}
console.timeEnd('Object')