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ak;ldjf;lakdjf
(version: 0)
Comparing performance of:
spread vs from
Created:
3 years ago
by:
Guest
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Script Preparation code:
function generateTestArray() { const result = []; for (let i = 0; i < 1000000; ++i) { result.push({ a: i, b: i / 2, r: 0, }); } return result; }
Tests:
spread
const array = generateTestArray(); const newMap = new Map(array); const foo = [...newMap.entries()];
from
const array = generateTestArray(); const newMap = new Map(array); const foo = Array.from(newMap.entries());
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
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Test case name
Result
spread
from
Fastest:
N/A
Slowest:
N/A
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's dive into the world of MeasureThat.net and explore what's being tested in this benchmark. **Benchmark Purpose** The purpose of this benchmark is to compare the performance of two approaches: using `Array.from()` and using the spread operator (`...`) to convert an array to a new array with entries. The test case uses a large array of 1 million objects, which is generated by a custom JavaScript function `generateTestArray()`. This function creates an array of objects with properties `a`, `b`, and `r`. **Approaches Compared** There are two approaches being compared: 1. **Using `Array.from()`**: The benchmark checks the performance of converting the array to a new array using the `Array.from()` method. 2. **Using the spread operator (`...`)**: The benchmark also checks the performance of using the spread operator to convert the array to a new array with entries. **Pros and Cons** **Array.from()** Pros: * More explicit and readable way to create an array from a collection * Can be used to create arrays from other types of collections, such as sets or maps Cons: * May incur additional overhead due to creating a new empty array and then copying the elements **Spread Operator (`...`)** Pros: * Concise and expressive syntax * Can be faster for large datasets since it avoids creating an intermediate array Cons: * Less explicit and less readable than `Array.from()` * Only works with arrays, not other types of collections **Other Considerations** Both approaches have their trade-offs. Using `Array.from()` can provide more control and flexibility, but may incur additional overhead. The spread operator is concise and expressive, but its performance benefits come at the cost of readability. **Library Usage** In this benchmark, no external libraries are used. However, it's worth noting that some JavaScript engines may have built-in optimizations or features that could affect the results. **Special JS Features or Syntax** This benchmark does not use any special JavaScript features or syntax beyond the standard ECMAScript specification. **Alternatives** If you're looking for alternative approaches to convert an array to a new array with entries, here are a few options: * Using `Array.prototype.map()`: This method returns a new array with the results of applying a provided function on every element in the original array. * Using `slice()` and then applying `map()` or other methods: This approach involves creating a copy of the array using `slice()`, and then applying another method to convert it to a new array with entries. Keep in mind that these alternatives may have different performance characteristics compared to `Array.from()` and the spread operator.
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Test about big arrays
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