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JavaScript spread operator vs Object.assign performance 2021
(version: 0)
Comparing performance of:
Using the spread operator vs Using Object.assign
Created:
4 years ago
by:
Guest
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Tests:
Using the spread operator
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);
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
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Test case name
Result
Using the spread operator
Using Object.assign
Fastest:
N/A
Slowest:
N/A
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
I'll break down the provided benchmark and its components to help explain what's being tested. **Benchmark Overview** The `MeasureThat.net` website allows users to create and run JavaScript microbenchmarks, comparing different approaches to specific tasks. In this case, we have two test cases: "Using the spread operator" and "Using Object.assign". The benchmark aims to measure the performance difference between these two methods of merging objects in JavaScript. **Options Compared** The two options being compared are: 1. **Spread Operator (`...`)**: This syntax was introduced in ECMAScript 2018 (ES2018) as a way to merge objects by spreading their properties into a new object. 2. **Object.assign()**: A built-in JavaScript method for merging one or more source objects into another target object. **Pros and Cons** * **Spread Operator (`...`)**: + Pros: - More concise and readable code - Easier to understand and maintain, especially for those familiar with the syntax + Cons: - May not be supported in older browsers or environments (e.g., Internet Explorer) - Can lead to slower performance due to string manipulation overhead * **Object.assign()**: + Pros: - Widely supported across modern browsers and environments - Efficient for merging large numbers of objects + Cons: - Less concise and more verbose code compared to the spread operator - May require additional effort to understand and maintain, especially for those unfamiliar with the method **Library Usage** There is no explicit library usage in the provided benchmark. However, it's worth noting that `Object.assign()` has been a part of the JavaScript standard library since ECMAScript 2015 (ES6), while the spread operator was introduced later as a syntax extension. **Special JS Feature or Syntax** The spread operator (`...`) is a new feature introduced in ECMAScript 2018. It allows for more concise and expressive code when working with objects, particularly when merging properties into a new object. While it may not be familiar to all developers, it has become an essential part of modern JavaScript development. **Alternative Approaches** If the spread operator is not supported or preferred, other alternatives for merging objects in JavaScript include: * Using `Array.prototype.reduce()` to merge objects * Utilizing libraries like Lodash or Underscore.js, which provide robust object merging functions Keep in mind that these alternative approaches might have different performance characteristics and usage patterns compared to the spread operator or `Object.assign()`.
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