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2spread vs concat vs unshift23
(version: 0)
spread vs concat vs unshift
Comparing performance of:
arrayUnshift123 vs arrayConcat123 vs arraySpread123
Created:
7 years ago
by:
Guest
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Tests:
arrayUnshift123
var array = [1,2,3]; array.unshift(0, 5, 9); if (array.length != 6) throw Error("Unfair")
arrayConcat123
var array = [1,2,3]; array = array.concat([0, 5, 9]) if (array.length != 6) throw Error("Unfair")
arraySpread123
var array = [1,2,3]; array = [0, 5, 9, ...array] if (array.length != 6) throw Error("Unfair")
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Suite status:
<idle, ready to run>
Run tests (3)
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Test case name
Result
arrayUnshift123
arrayConcat123
arraySpread123
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 definition represents three different approaches to adding elements to an array in JavaScript: using `unshift()`, `concat()`, and spread syntax (`...`). **Options being compared:** 1. **`unshift()`**: This method adds one or more elements to the beginning of an array. 2. **`concat()`**: This method returns a new array that is the result of concatenating the original array with another array or iterable. 3. **Spread syntax (`...`)**: This method uses the spread operator to create a new array by copying elements from an existing array. **Pros and Cons of each approach:** 1. **`unshift()`**: * Pros: Efficient for small arrays, as it only requires shifting elements down after adding. * Cons: May be slower than `concat()` or spread syntax for large arrays, since it needs to shift all elements in the array. 2. **`concat()`**: * Pros: More flexible and efficient for large arrays, as it can create a new array without modifying the original one. * Cons: Creates a new array object, which may lead to increased memory usage compared to `unshift()`. 3. **Spread syntax (`...`)**: * Pros: Creates a shallow copy of the original array, preserving its structure and references. * Cons: May be slower than `concat()` or `unshift()` for large arrays, since it needs to create a new array. **Library usage:** None in this benchmark definition. **Special JS features:** The spread syntax (`...`) is a modern JavaScript feature introduced in ECMAScript 2015 (ES6). It allows creating new arrays by spreading elements from an existing array or iterable. Now, let's look at the individual test cases: * **`arrayUnshift123`**: Tests `unshift()` method with three elements: `[1,2,3]`, `0`, `5`, and `9`. The expected length of the array is 6. * **`arrayConcat123`**: Tests `concat()` method with three elements: `[1,2,3]`, `[0,5,9]`. The expected length of the array is 6. * **`arraySpread123`**: Tests spread syntax (`...`) with three elements: `[1,2,3]`, `0`, `5`, and `9`. The expected length of the array is 6. **Other alternatives:** Depending on the specific use case, other methods like `push()` or using a library like Lodash's `unionByOne` could be used instead. However, these methods might have different performance characteristics compared to `unshift()`, `concat()`, and spread syntax. In summary, MeasureThat.net provides a helpful comparison of three approaches for adding elements to an array in JavaScript: `unshift()`, `concat()`, and spread syntax (`...`). By understanding the pros and cons of each approach, developers can choose the most efficient method for their specific use case.
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