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Concat, vs spread vs array from
(version: 0)
Comparing performance of:
Concat vs Spread vs From
Created:
6 years ago
by:
Guest
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Tests:
Concat
var users = ["user1", "user2"] var newUser = ["newUser"] var joined = newUser.concat(users)
Spread
var users = ["user1", "user2"] var newUser = ["newUser", ...users]
From
var users = ["user1", "user2"] var newUser = Array.from(users) newUser.push("newUser")
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (3)
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Test case name
Result
Concat
Spread
From
Fastest:
N/A
Slowest:
N/A
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
I'd be happy to explain the benchmark. **Benchmark Overview** The benchmark is designed to compare the performance of three ways to concatenate an array in JavaScript: using the `concat()` method, using the spread operator (`...`), and using the `Array.from()` method. The benchmark aims to determine which approach is the most efficient. **Options Compared** 1. **Concat() Method**: This method creates a new array by copying elements from the original array. 2. **Spread Operator ()...**: This method creates a new array by spreading the elements of an existing array. 3. **Array.from() Method**: This method creates a new array from an iterable (such as an array) and returns its length. **Pros and Cons** * **Concat() Method**: + Pros: Simple and easy to understand, widely supported in older browsers. + Cons: Creates a new array, which can be inefficient for large datasets. * **Spread Operator (...)**: + Pros: More modern and efficient than `concat()`, creates a new array only when necessary. + Cons: Requires newer JavaScript versions (ES6+) and may not work in older browsers. * **Array.from() Method**: + Pros: Efficient, as it uses the `length` property to create a shallow copy of the original array. Also, preserves any methods or symbols on the original array. + Cons: May be less familiar to developers who are not accustomed to using `Array.from()`. **Library and Special JS Feature** In this benchmark, no specific libraries are used beyond the JavaScript core functionality. **Special JS Features** None of the test cases use special JavaScript features. However, keep in mind that the spread operator was introduced in ECMAScript 2015 (ES6) and may not work in older browsers. **Other Alternatives** If you need to concatenate arrays in a different way, consider using other methods such as: * Using `push()` method with an array parameter: `arr.push(newElement)` * Using the `+` operator with string concatenation: `(newElement + arr)` (note that this creates a new string) * Using `slice()` method to create a shallow copy of the original array: `arr.slice(0, arr.length + 1).push(newElement)` However, these alternatives are likely less efficient than the three methods compared in this benchmark.
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