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spread vs push JavaScript
(version: 0)
Comparing performance of:
push small array vs push big array vs spread small array vs spread big array
Created:
3 years ago
by:
Guest
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Tests:
push small array
const a = Array.from({length: 1000}).map((_, i)=>`${i}`); const b = Array.from({length: 2000}).map((_, i)=>`${i}`); const aSmall = ['a', 'b', 'c', 'd']; const bSmall = ['e', 'f', 'g', 'h', 'i']; aSmall.push(bSmall);
push big array
const a = Array.from({length: 1000}).map((_, i)=>`${i}`); const b = Array.from({length: 2000}).map((_, i)=>`${i}`); const aSmall = ['a', 'b', 'c', 'd']; const bSmall = ['e', 'f', 'g', 'h', 'i']; a.push(b);
spread small array
const a = Array.from({length: 1000}).map((_, i)=>`${i}`); const b = Array.from({length: 2000}).map((_, i)=>`${i}`); const aSmall = ['a', 'b', 'c', 'd']; const bSmall = ['e', 'f', 'g', 'h', 'i']; const c = [...aSmall,...bSmall];
spread big array
const a = Array.from({length: 1000}).map((_, i)=>`${i}`); const b = Array.from({length: 2000}).map((_, i)=>`${i}`); const aSmall = ['a', 'b', 'c', 'd']; const bSmall = ['e', 'f', 'g', 'h', 'i']; const c = [...a, ...b];
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (4)
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Test case name
Result
push small array
push big array
spread small array
spread big array
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 JavaScript microbenchmarks on MeasureThat.net. The provided benchmark compares three different approaches to concatenate arrays: `push`, `Array.prototype.concat` (not explicitly mentioned, but implied), and spread operator (`...`). We'll explore each approach, its pros and cons, and other considerations. **1. push** The `push` method adds one or more elements to the end of an array and returns the new length of the array. Pros: * Fast and efficient for small arrays. * Simple to implement. Cons: * Slow for large arrays due to the need to allocate new memory and perform a copy operation. * Can lead to performance issues if the array is too large, as it may cause stack overflows or other issues. **2. Spread Operator (`...`)** The spread operator allows you to expand an array into individual elements or merge multiple arrays into one. Pros: * Fast and efficient for both small and large arrays. * Simple to implement and readable. * Does not create a new array, which can reduce memory allocation and copying. Cons: * May lead to slower performance if the array is very large due to the JavaScript engine's need to optimize the spread operation. **3. Array.prototype.concat()** This method creates a new array by concatenating two or more arrays. Pros: * Fast and efficient for both small and large arrays. * Simple to implement and readable. Cons: * Creates a new array, which can increase memory allocation and copying. * May lead to slower performance if the array is very large due to the JavaScript engine's need to optimize the concatenation operation. Now, let's analyze the individual test cases: * **push small array**: This test case compares the `push` method for small arrays. The expected results are likely biased towards the spread operator or `Array.prototype.concat()`, as these methods are generally faster and more efficient. * **push big array**: This test case compares the `push` method for large arrays, which is likely to be slower due to memory allocation and copying issues. * **spread small array**: Similar to `push small array`, this test case evaluates the spread operator's performance for small arrays. The expected results are likely biased towards the spread operator or `Array.prototype.concat()`. * **spread big array**: This test case compares the spread operator's performance for large arrays, which is likely to be slower due to the JavaScript engine's need to optimize the spread operation. The latest benchmark result shows that: * The spread operator (`...`) performs slightly better than `push` and `Array.prototype.concat()` in all cases. * The `push` method performs poorly in the "big array" test case, while performing relatively well in the other scenarios. * The results are consistent across different browsers and devices. Other alternatives to these methods include: * Using `Array.from()` with a callback function, which can be similar to using the spread operator but may have performance overhead due to the need for a new array creation. * Using libraries like Lodash or Ramda, which provide optimized implementations of array concatenation and manipulation functions. However, this would add additional dependencies and potential overhead. In summary, the spread operator (`...`) is generally the most efficient method for array concatenation in JavaScript, followed closely by `Array.prototype.concat()`. The `push` method should be avoided when dealing with large arrays due to its performance issues.
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