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Run results for: Map vs Object (Lookup then delete keys) Performance

Lookup of map vs object then delete keys

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Run details:
Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:135.0) Gecko/20100101 Firefox/135.0
Firefox 135
Windows
Desktop
2 months ago
Test name Executions per second
Conspicuous Map lookup & delete 2438.3 Ops/sec
Conspicuous Obj lookup & delete 130.9 Ops/sec
Script Preparation code:
​x
 
var keyCount = 16384
var keys = []
var map = new Map()
var obj = {}
​
​
// 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 = Math.random()
  keys.push(key)
  map.set(key,val)
  obj[key] = val
}
​
Tests:

  • Conspicuous Map lookup & delete

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

  • Conspicuous Obj lookup & delete

     
    for (let i=0; i<keyCount; i++) {
      let seed = Math.random()
      let key = getConspicuousKey(seed)
      a = obj[key]
      if (a) delete obj[key]
    }