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JS object copy spread vs assign spin@
(version: 0)
Comparing performance of:
Assign vs Spread
Created:
7 years ago
by:
Guest
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Tests:
Assign
const object1 = {type1: "gilada"}; const object2 = {type2: "gilada"}; const object3 = {type3: "gilada"}; const copy = Object.assign({}, Object.assign(object1, Object.assign(object2, object3)));
Spread
const object1 = {type1: "gilada"}; const object2 = {type2: "gilada"}; const object3 = {type3: "gilada"}; const copy = {...object1, ...object2, ...object3 };
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Suite status:
<idle, ready to run>
Run tests (2)
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Test case name
Result
Assign
Spread
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 explanation into smaller parts to make it easier to understand. **What is being tested?** The provided JSON represents a JavaScript microbenchmark that tests two approaches for creating a shallow copy of an object: using `Object.assign()` (assign) and using the spread operator (`...`) with three objects, `object1`, `object2`, and `object3`. The benchmark aims to measure which approach is faster. **Options compared** The benchmark compares two options: 1. **Assign**: Using `Object.assign()` to create a shallow copy of an object. 2. **Spread**: Using the spread operator (`...`) with three objects, `object1`, `object2`, and `object3`, to create a shallow copy of an object. **Pros and cons of each approach** ### Assign * Pros: + Easy to understand and implement. + Widely supported by most browsers and JavaScript engines. * Cons: + Can be slower due to the overhead of function calls. + May lead to unexpected behavior if used with complex objects or nested arrays. ### Spread * Pros: + Fast and efficient, as it only involves object property assignments. + Reduces the risk of unexpected behavior compared to `Object.assign()`. * Cons: + Less widely supported by older browsers and JavaScript engines (e.g., older versions of Chrome and Firefox). + May require additional imports or polyfills for compatibility. **Library and purpose** In this benchmark, there is no specific library being used. The `Object` object is a built-in part of the JavaScript language, and the spread operator (`...`) is also a native feature. **Special JS features or syntax** There are no special JavaScript features or syntaxes being tested in this benchmark. **Other alternatives** If you were to implement an alternative approach for creating a shallow copy of an object, some options might include: 1. **Loose equality assignment**: Using `const copy = {type1: value, type2: value, type3: value };` 2. **Array.prototype.slice()**: Using `const copy = Array.prototype.slice.call([object1, object2, object3]);` However, these alternatives are not being tested in this specific benchmark. In summary, the benchmark tests two approaches for creating a shallow copy of an object using JavaScript: the spread operator and `Object.assign()`. The spread operator is faster but less widely supported, while `Object.assign()` is more widely supported but may be slower.
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