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Array push vs
(version: 0)
Comparing performance of:
a vs b
Created:
4 years ago
by:
Guest
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Tests:
a
const a = []; for( let i=0; i<100000;i++ ) a.push( Math.random() );
b
const a = []; for( let i=0; i<100000;i++ ) a[ a.length] = Math.random();
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Suite status:
<idle, ready to run>
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Test case name
Result
a
b
Fastest:
N/A
Slowest:
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
I'd be happy to explain the benchmark and its results. **What is being tested?** The provided JSON represents two individual test cases for a JavaScript microbenchmark: `Array push vs`. The goal of this benchmark is to compare the performance of two different ways of pushing elements onto an array in JavaScript. **Options being compared** There are two options being compared: 1. **`a.push(Math.random())`**: This option uses the `push()` method to add a new element to the end of the array. 2. **`a[a.length] = Math.random()`**: This option uses the syntax `a[a.length] = ...` to access and assign a value to the last index of the array. **Pros and Cons of each approach** 1. **`a.push(Math.random())`**: * Pros: Easy to read and write, concise, and efficient in most cases. * Cons: May have performance overhead due to the `push()` method's internal implementation. 2. **`a[a.length] = Math.random()`**: * Pros: Direct access to the last index of the array can be faster for large arrays or when working with a fixed-size array. * Cons: Less readable and more verbose, may require careful handling of edge cases (e.g., `undefined` or `null` values). **Other considerations** * The use of `Math.random()` to generate random numbers introduces additional overhead due to the cost of generating random numbers. * Both options assume that the array is not yet initialized; if the array needs to be preinitialized, the performance difference may be less pronounced. **Library usage** None of the provided code snippets use any external libraries. **Special JS features or syntax** There are no special JavaScript features or syntax used in these benchmark tests. They only rely on standard JavaScript syntax and built-in functions. **Alternatives** If you need to compare other aspects of array manipulation, such as: * **`a[0] = ...`**: Accessing the first element of an array. * **`a.indexOf(...)`**: Finding a specific value in an array. * **`Array.prototype.forEach()`**: Iterating over an array using a callback function. You can create additional test cases to compare these different approaches.
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