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JavaScript assignment vs Object.assign performance vs Spread performance
(version: 0)
Comparing performance of:
Equal vs Object.assign vs Spread
Created:
3 years ago
by:
Guest
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Tests:
Equal
const firstObject = { sampleData: ()=>{return 1+1;} } const secondObject = { moreData: 'foo bar' } let finalObject = {}; finalObject['firstObject'] = firstObject.sampleData; finalObject['secondObject'] = secondObject.moreData;
Object.assign
const firstObject = { sampleData: ()=>{return 1+1;} } const secondObject = { moreData: 'foo bar' } const finalObject = Object.assign(firstObject, secondObject);
Spread
const firstObject = { sampleData: ()=>{return 1+1;} } const secondObject = { moreData: 'foo bar' } const finalObject = {...firstObject, ...secondObject};
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (3)
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Test case name
Result
Equal
Object.assign
Spread
Fastest:
N/A
Slowest:
N/A
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the provided benchmark and explain what is tested, compared options, pros and cons of those approaches, and other considerations. **Benchmark Overview** The test cases are designed to measure the performance differences between three methods: object assignment (`Object.assign`), spread syntax (using the `...` operator), and manual property assignment using a string notation (`finalObject['firstObject'] = firstObject.sampleData; finalObject['secondObject'] = secondObject.moreData;`). **Method 1: Object Assign** `Object.assign` is a built-in JavaScript method that assigns properties from one or more source objects to another object. In this benchmark, it's used to assign `sampleData` and `moreData` properties from the `firstObject` and `secondObject` respectively to the `finalObject`. **Pros:** 1. Concise syntax 2. Easy to read and understand **Cons:** 1. Performance overhead due to method call and object creation 2. May not be suitable for very large objects or deeply nested data structures In modern JavaScript, `Object.assign` is a widely used and efficient way to merge objects. However, in this specific benchmark, its performance might be affected by the additional overhead of the method call. **Method 2: Spread Syntax** The spread syntax (using the `...` operator) creates a new object with the properties from the source objects. ```javascript const finalObject = {...firstObject, ...secondObject}; ``` **Pros:** 1. Efficient and lightweight 2. Easy to read and understand **Cons:** 1. May be slower than `Object.assign` for very large objects or deeply nested data structures 2. Can be less intuitive for beginners due to the spread syntax being a relatively recent addition to JavaScript The spread syntax has become increasingly popular in modern JavaScript, offering a concise and readable way to merge objects. **Method 3: Manual Property Assignment** This approach uses string notation to assign properties to the `finalObject`. ```javascript finalObject['firstObject'] = firstObject.sampleData; finalObject['secondObject'] = secondObject.moreData; ``` **Pros:** 1. No performance overhead due to method calls or object creation **Cons:** 1. Less concise and harder to read than `Object.assign` or spread syntax 2. More prone to errors due to the need for explicit property names This approach is often used in older JavaScript versions or when working with legacy codebases. **Other Considerations** * The benchmark results show that Chrome 111 performs best with the spread syntax, followed by `Object.assign`, and then manual property assignment. * The performance differences are likely due to the overhead of method calls and object creation in `Object.assign`. * The benchmark results also suggest that manual property assignment may not be suitable for large-scale applications. **Alternatives** Other alternatives for merging objects include: 1. Using a library like Lodash or Underscore.js, which provide more comprehensive set of utility functions. 2. Employing alternative data structures, such as arrays or graphs, to store and manipulate data. 3. Utilizing other JavaScript methods, like `Object.create()` or `Array.prototype.slice()`, for object manipulation. Keep in mind that the choice of method depends on specific requirements, performance constraints, and personal preference.
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