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JavaScript spread operator vs Object.assign performance replacing values
(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', replace: "replace" } const secondObject = { moreData: 'foo bar', replace: "replaced" } const finalObject = { ...firstObject, ...secondObject };
Using Object.assign
const firstObject = { sampleData: 'Hello world', replace: "replace" } const secondObject = { moreData: 'foo bar', replace: "replaced" } 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):
Let's break down what's being tested in this benchmark and explore the options compared, pros and cons, and other considerations. **What is being tested?** The benchmark measures the performance of two ways to merge objects in JavaScript: using the spread operator (`...`) and `Object.assign()`. **Options compared:** 1. **Spread Operator (Rest Spread Syntax)**: This syntax was introduced in ECMAScript 2015 (ES6) as a way to create new objects by merging existing ones. It's denoted by three dots (`...`) followed by an object literal. 2. **Object.assign()**: This method is used to merge all or part of one or more source objects into a target object. **Pros and Cons:** * **Spread Operator (Rest Spread Syntax)**: + Pros: More readable, concise code; easier to understand the intention behind merging objects. + Cons: May be slower than `Object.assign()` due to the overhead of creating a new object literal. * **Object.assign()**: + Pros: Faster performance compared to the spread operator; + Cons: Less readable and more verbose code, which can make it harder to understand the intention behind merging objects. **Library used:** None, this is a native JavaScript implementation. **Special JS feature or syntax:** The benchmark uses rest spread syntax (`...`), which was introduced in ECMAScript 2015 (ES6). This syntax allows for more concise and readable code when merging objects. **Benchmark preparation code and test cases:** The benchmark preparation code creates two object literals, `firstObject` and `secondObject`, with some sample data. The final object, `finalObject`, is created by merging these two objects using either the spread operator or `Object.assign()`. Two test cases are defined: 1. Using the spread operator (`const finalObject = { ...firstObject, ...secondObject }`); 2. Using `Object.assign()` (`const finalObject = Object.assign(firstObject, secondObject);`) **Other alternatives:** If you wanted to use other methods for merging objects in JavaScript, some alternatives could be: * **Merge() method**: Introduced in ECMAScript 2020 (ES2020), this method provides a more concise and expressive way of merging objects. * **Object.create()**: This method allows you to create a new object by passing another object as the prototype. You can then use the `Object.assign()` method or other methods to merge properties into the new object. However, for most use cases, the spread operator (`...`) and `Object.assign()` are still the most commonly used and efficient ways to merge objects in JavaScript.
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