Run results for: Building objects

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/64.0.3282.186 Safari/537.36

Browser: Chrome 64

Operating system: Mac OS X 10.12.6

Device Platform: Other

Date tested: 2025 years ago

Test name	Executions per second
Iterate keys to build objects	2428.6 Ops/sec
Build new fn	5418.5 Ops/sec

Script Preparation code:

window.keys = [];
window.values = [];
const NUM_KEYS = 100;
const COLLECTION_SIZE = 500;
const s = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
function randString(len) {
  return Array(len).fill('').map(() => s.charAt(Math.floor(Math.random() * s.length))).join('');
}

// Build 100 keys
for (let i = 0; i < NUM_KEYS; i++) {
  keys[0] = randString(10);
}

// Fill array-of-arrays with values
for (let i = 0; i < COLLECTION_SIZE; i++) {
  values[i] = [];
  for (let j = 0; j < NUM_KEYS; j++) {
    values[i][j] = randString(10);
  }
}

Tests:

Iterate keys to build objects
const collection = Array(values.length); for (let i = 0; i < values.length; i++) { const obj = collection[i] = {}; const theseVals = values[i]; for (let j = 0; j < keys.length; j++) { obj[keys[j]] = theseVals[j]; } }
Build new fn
function makeFlipFn(keys) { return new Function('v', 'idx', ` return { ${keys.map((key, i) => `"${key}": v[${i}][idx]`).join(',')} } `); } const buildFn = makeFlipFn(keys); const collection = Array(values.length); for (let i = 0; i < values.length; i++) { collection[i] = buildFn(values[i], i); }

Run results for: Building objects

Benchmarking building a collection of models from arrays of keys & values

Iterate keys to build objects

Build new fn