ECMAScript: Map write optimization

benchmark.js

var N = 1000000;
var RUNS = 100;
const Method = Object.freeze({ 'GET': 'GET' });
const relation = 'resource';
const store = [];

const tag = Object.freeze((m, r, p) => m + '/' + r + '/' + p);

const values = new Array(N).fill(0).map((n, i) => ({ id: i + 1, data: 'item' + i }));

console.log(`--- Map Test Start (N=${N}, Runs=${RUNS}) ---`);

function runTest(name, callback) {
  let totalTime = 0;
  for (let r = 0; r < RUNS; r++) {
    const start = performance.now();
    callback();
    const end = performance.now();
    totalTime += (end - start);
  }
  const avgTime = (totalTime / RUNS).toFixed(2);
  console.log(`${name}: ${avgTime} ms (Average)`);
}


runTest("1. C-style, cached tags Array.map", () => {
  const tags = Object.freeze(values.map(value => tag(Method['GET'], relation, value.id)));
  const l = values.length;
  const map1 = new Map(store);
  for (let i = 0; i < l; i++) {
    map1.set(tags[i], values[i]);
  }
});

runTest("2. C-Style, cached tags Array.from", () => {
  const tags = Object.freeze(Array.from(values, value => tag(Method['GET'], relation, value.id)));
  const map2 = new Map(store);
  const l = values.length;
  for (let i = 0; i < l; i++) {
    map2.set(tag(Method['GET'], relation, values[i].id), values[i]);
  }
});

runTest("3. C-Style, inlined tag", () => {
  const map2 = new Map(store);
  const l = values.length;
  for (let i = 0; i < l; i++) {
    map2.set(tag(Method['GET'], relation, values[i].id), values[i]);
  }
});

runTest("4. C-Style, inlined string concat", () => {
  const map2 = new Map(store);
  const l = values.length;
  for (let i = 0; i < l; i++) {
    map2.set(Method['GET'] + '/' + relation + '/' + values[i].id, values[i]);
  }
});

runTest("5. C-Style, inlined template string", () => {
  const map2 = new Map(store);
  const l = values.length;
  for (let i = 0; i < l; i++) {
    map2.set(`${Method['GET']}/${relation}/${values[i].id}`, values[i]);
  }
});

runTest("5. C-Style, inlined template string without Method", () => {
  const map2 = new Map(store);
  const l = values.length;
  for (let i = 0; i < l; i++) {
    map2.set(`GET/${relation}/${values[i].id}`, values[i]);
  }
});


console.log("--- Map Test End ---");

Chrome 142.0.7444.176 (Official Build) (arm64)

--- Map Test Start (N=1000000, Runs=100) ---
1. C-style, cached tags Array.map: 322.01 ms (Average)
2. C-Style, cached tags Array.from: 414.11 ms (Average)
3. C-Style, inlined tag: 277.00 ms (Average)
4. C-Style, inlined string concat: 275.94 ms (Average)
5. C-Style, inlined template string: 281.58 ms (Average)
5. C-Style, inlined template string without Method: 261.91 ms (Average)
--- Map Test End ---

Deno 2.5.6 macOS 26.1 (25B78)

--- Map Test Start (N=1000000, Runs=100) ---
1. C-style, cached tags Array.map: 313.87 ms (Average)
2. C-Style, cached tags Array.from: 458.73 ms (Average)
3. C-Style, inlined tag: 370.30 ms (Average)
4. C-Style, inlined string concat: 395.40 ms (Average)
5. C-Style, inlined template string: 413.71 ms (Average)
5. C-Style, inlined template string without Method: 387.21 ms (Average)
--- Map Test End ---

Node.js v25.1.0 macOS 26.1 (25B78)

--- Map Test Start (N=1000000, Runs=100) ---
1. C-style, cached tags Array.map: 343.22 ms (Average)
2. C-Style, cached tags Array.from: 511.34 ms (Average)
3. C-Style, inlined tag: 407.72 ms (Average)
4. C-Style, inlined string concat: 368.57 ms (Average)
5. C-Style, inlined template string: 368.17 ms (Average)
5. C-Style, inlined template string without Method: 353.79 ms (Average)
--- Map Test End ---