Run results for: ES6 Map Merge vs forEach

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.142 Safari/537.36

Browser: Chrome 75

Operating system: Mac OS X 10.14.6

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
Merge	3726.6 Ops/sec
Loop	5646.7 Ops/sec

Script Preparation code:

const entries1 = [];
const entries2 = [];
for (let i = 0; i < 1000; i++) {
  entries1[i] = [i , i];
}
for (let i = 0; i < 1000; i++) {
  entries2[i] = [i + 500, i + 600];
}
const pathSegmentMap = new Map(entries1);
const newSegmentMap = new Map(entries2);

Tests:

Merge
const entries1 = []; const entries2 = []; for (let i = 0; i < 1000; i++) { entries1[i] = [i , i]; } for (let i = 0; i < 1000; i++) { entries2[i] = [i + 500, i + 600]; } const pathSegmentMap = new Map(entries1); const newSegmentMap = new Map(entries2); const mergeMap = new Map([...pathSegmentMap, ...newSegmentMap]);
Loop
const entries1 = []; const entries2 = []; for (let i = 0; i < 1000; i++) { entries1[i] = [i , i]; } for (let i = 0; i < 1000; i++) { entries2[i] = [i + 500, i + 600]; } const pathSegmentMap = new Map(entries1); const newSegmentMap = new Map(entries2); newSegmentMap.forEach((value, key) => { pathSegmentMap.set(key, value); });

Run results for: ES6 Map Merge vs forEach

Merge

Loop