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Run results for: Map vs WeakMap (real-world) Performance

Lookup of map vs object (in a real-world test format)

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Run details:
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.0.0 Safari/537.36
Chrome 124
Windows
Desktop
10 months ago
Test name Executions per second
Conspicuous Map lookup 44.2 Ops/sec
Conspicuous WeakMap lookup 46.0 Ops/sec
Conspicuous Map lookup 2 44.6 Ops/sec
Conspicuous WeakMap lookup 2 46.4 Ops/sec
Script Preparation code:
​x
 
var keyCount = 16384
var keys = []
var map = new Map()
var weakmap = new WeakMap()
​
​
// Hide lookup keys to prevent V8 cheating (AKA Optimizing)
var getConspicuousKey = seed => keys[Math.floor(seed * keyCount)]
​
​
// Setup out test objects w/ random values
for (let i=0; i<keyCount; i++) {
  let val = Math.random()
  let key = {}
  keys.push(key)
  map.set(key,val)
  weakmap.set(key,val)
}
​
Tests:

  • Conspicuous Map lookup

     
    for (let i=0; i<keyCount; i++) {
      let seed = Math.random()
      let key = getConspicuousKey(seed)
      a = map.get(key)
    }

  • Conspicuous WeakMap lookup

     
    for (let i=0; i<keyCount; i++) {
      let seed = Math.random()
      let key = getConspicuousKey(seed)
      a = weakmap.get(key)
    }

  • Conspicuous Map lookup 2

     
    for (let i=0; i<keyCount; i++) {
      let seed = Math.random()
      let key = getConspicuousKey(seed)
      a = map.get(key)
    }

  • Conspicuous WeakMap lookup 2

     
    for (let i=0; i<keyCount; i++) {
      let seed = Math.random()
      let key = getConspicuousKey(seed)
      a = weakmap.get(key)
    }