Run results for: Map() delete while iterating vs clear

When iterating over a Map and clearing after iteration is required, is it faster to remove items at each iteration step or is it faster to iterate and then clear() the entire Map afterwards?

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/112.0.5615.204 Safari/537.36

Browser: Chrome 112

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Benchmark engine: Benchmark.js

Iterate + delete

121.1M/s

Iterate + clear

6.7M/s

View exact numbers

Test name	Executions per second
✓ Iterate + delete	121,070,192 Ops/sec
Iterate + clear	6,670,017 Ops/sec

Script Preparation code:

var dummy = 0;
var map = new Map(new Array(100).fill(null).map((_, i) => [
  function(incrementBy) {
  	dummy += incrementBy;
  },
  { incrementBy: i }
]));

Tests:

Iterate + clear
for (const [fn, obj] of map) { fn(obj.incrementBy); } map.clear();
Iterate + delete
for (const [fn, obj] of map) { fn(obj.incrementBy); map.delete(fn); }