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Spread operator vs. slice
(version: 0)
Creating a "new" array reference every time
Comparing performance of:
Spread operator vs Slice()
Created:
8 years ago
by:
Guest
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Tests:
Spread operator
var n = []; while(true) { n.push('asdf'); n = [...n]; if(n.length >= 100000) break; }
Slice()
var n = []; while(true) { n.push('asdf'); n.slice(); if(n.length >= 100000) break; }
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Suite status:
<idle, ready to run>
Run tests (2)
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Test case name
Result
Spread operator
Slice()
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 benchmark definition and test cases to understand what is being tested. **Benchmark Definition** The benchmark definition describes two approaches to creating an array reference every time: 1. **Spread Operator**: This approach uses the spread operator (`...`) to create a new array reference from the existing array `n`. The syntax `n = [...n];` creates a shallow copy of the array, which is then assigned back to `n`. 2. **Slice()**: This approach uses the `slice()` method to create a new array reference from the existing array `n`. **Options Compared** The two approaches are compared in terms of performance. **Pros and Cons** * **Spread Operator**: + Pros: Simple, concise syntax; works with arrays of any type. + Cons: Can be slower due to the overhead of creating a new array reference. * **Slice()**: + Pros: Efficient use of `slice()` method, which is optimized by most browsers. + Cons: Requires specific method call (`slice()`), which may not be as intuitive. **Library** In this benchmark, no external libraries are used. However, the `slice()` method is a built-in method in JavaScript. **Special JS Feature or Syntax** The spread operator (`...`) was introduced in ECMAScript 2015 (ES6) and has since become a standard feature in modern browsers. The use of `slice()` also relies on the fact that most browsers have optimized implementations of this method. **Other Alternatives** If you were to implement these approaches using a different language or framework, you might consider: * Using an array constructor (`Array.from()`) instead of spread operator. * Using a library like Lodash or Ramda for array manipulation. In JavaScript, alternative approaches could include: * Using `Object.assign()` or other methods to create a new array reference. * Implementing custom logic to create a new array reference from scratch. However, these alternatives are not relevant in this specific benchmark, which focuses on the performance comparison of spread operator and slice(). Overall, this benchmark provides a simple yet informative way to compare the performance of two common approaches to creating an array reference in JavaScript.
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