Run results for: Looping frozen object vs non-frozen object

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:133.0) Gecko/20100101 Firefox/133.0

Browser: Firefox 133

Operating system: Mac OS X 10.15

Device Platform: Desktop

Date tested: one year ago

Loop non-frozen object

5.2M/s

Loop frozen object

5.2M/s

View exact numbers

Test name	Executions per second
✓ Loop non-frozen object	5,210,472 Ops/sec
Loop frozen object	5,199,910 Ops/sec

HTML Preparation code:

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Script Preparation code:

const birdSpecies = {
  forest: {
    species: [
      {
        name: "Northern Cardinal",
        physicalCharacteristics: {
          color: "Red",
          size: "Medium",
          beakType: "Conical"
        },
        diet: {
          primary: "Seeds",
          secondary: "Fruits"
        },
        habitat: "Woodlands and forests"
      },
      {
        name: "Woodpecker",
        physicalCharacteristics: {
          color: "Black, White, and Red",
          size: "Medium",
          beakType: "Chisel-shaped"
        },
        diet: {
          primary: "Insects",
          secondary: "Tree sap"
        },
        habitat: "Wooded areas"
      }
    ]
  },
  desert: {
    species: [
      {
        name: "Roadrunner",
        physicalCharacteristics: {
          color: "Brown and White",
          size: "Medium",
          beakType: "Long and Slim"
        },
        diet: {
          primary: "Insects",
          secondary: "Small reptiles"
        },
        habitat: "Desert and arid regions"
      },
      {
        name: "Cactus Wren",
        physicalCharacteristics: {
          color: "Brown with streaks",
          size: "Small",
          beakType: "Curved"
        },
        diet: {
          primary: "Insects",
          secondary: "Seeds"
        },
        habitat: "Cacti and desert shrubs"
      }
    ]
  },
  wetlands: {
    species: [
      {
        name: "Great Blue Heron",
        physicalCharacteristics: {
          color: "Blue-gray",
          size: "Large",
          beakType: "Long and Sharp"
        },
        diet: {
          primary: "Fish",
          secondary: "Amphibians"
        },
        habitat: "Wetlands and marshes"
      },
      {
        name: "American Coot",
        physicalCharacteristics: {
          color: "Dark gray with white bill",
          size: "Medium",
          beakType: "Flat and short"
        },
        diet: {
          primary: "Aquatic plants",
          secondary: "Small invertebrates"
        },
        habitat: "Lakes and wetlands"
      }
    ]
  }
}

const frozenObject = Object.freeze(birdSpecies)
const nonFrozenObject = birdSpecies

Tests:

Loop frozen object
function doStuff(value) { // } for (const habitat in frozenObject) { const data = frozenObject[habitat]; for (const bird of data.species) { for (const key in bird.physicalCharacteristics) { const value = bird.physicalCharacteristics[key]; doStuff(value); } for (const key in bird.diet) { const value = bird.diet[key]; doStuff(value); } } }
Loop non-frozen object
function doStuff(value) { // } for (const habitat in nonFrozenObject) { const data = frozenObject[habitat]; for (const bird of data.species) { for (const key in bird.physicalCharacteristics) { const value = bird.physicalCharacteristics[key]; doStuff(value); } for (const key in bird.diet) { const value = bird.diet[key]; doStuff(value); } } }