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Run results for: JavaScript spread operator vs Object.assign performance immutable

Performance of object spread vs Object.assign when while preserving previous data.

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Run details:
Mozilla/5.0 (iPhone; CPU iPhone OS 14_0 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/14.0 Mobile/15E148 Safari/604.1
Mobile Safari 14
iOS 14.0
Mobile
4 years ago
Test name Executions per second
Using the spread operator 1361068.6 Ops/sec
Using Object.assign 2432187.2 Ops/sec
Using Object.assign no mutation 2073789.5 Ops/sec
Tests:

  • Using the spread operator

    AخA
     
    const firstObject = { sampleData: 'Hello world' }
    const secondObject = { moreData: 'foo bar' }
    const finalObject = {
        ...firstObject,
        ...secondObject
    };

  • Using Object.assign

     
    const firstObject = { sampleData: 'Hello world' }
    const secondObject = { moreData: 'foo bar' }
    const finalObject = Object.assign(firstObject, secondObject);

  • Using Object.assign no mutation

     
    const firstObject = { sampleData: 'Hello world' }
    const secondObject = { moreData: 'foo bar' }
    const finalObject = Object.assign({}, firstObject, secondObject);