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Array.from vs Spread1
(version: 0)
Comparing performance of:
Array.from vs Spread
Created:
6 years ago
by:
Guest
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Tests:
Array.from
var fooSet = new Set(); for(var i=0;i<8;i++) { fooSet.add(i); } var other = Array.from(fooSet);
Spread
var fooSet = new Set(); for(var i=0;i<8;i++) { fooSet.add(i); } var other = [...fooSet];
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Suite status:
<idle, ready to run>
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Test case name
Result
Array.from
Spread
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! **Benchmark Overview** The provided benchmark compares two approaches for creating an array from a Set: `Array.from()` and the spread operator (`...`). The test creates a Set with 8 elements and then converts it to an array using each method. The goal is to determine which approach is faster. **Options Compared** Two options are being compared: 1. **`Array.from()`**: This method takes an iterable (like a Set) as an argument and returns a new array containing the same values. 2. **Spread Operator (`...`)**: This operator creates a new array by spreading out the elements of another iterable. **Pros and Cons** **`Array.from()`** Pros: * More explicit and readable, as it clearly conveys the intention to create an array from a Set. * May be more efficient due to the overhead of iterating over the Set's values. Cons: * May introduce unnecessary overhead due to the iteration. **Spread Operator (`...`)** Pros: * Often faster, since it can use the underlying implementation details of the Set (e.g., its internal array representation) to create the new array. * Can be more concise and readable for simple cases. Cons: * Less explicit and readable, as it relies on a somewhat opaque operator syntax. * May not work correctly if the Set contains non-array values or if the spread operation is used incorrectly. **Library and Purpose** In both benchmark definitions, `Set` is a built-in JavaScript object that provides a collection of unique values. It's created using the `new Set()` constructor, which initializes an empty Set. **Special JS Feature/Syntax** The spread operator (`...`) is a new feature introduced in ECMAScript 2015 (ES6). It allows creating a new array by spreading out the elements of another iterable. **Other Considerations** When working with Sets and arrays, it's essential to consider performance implications. In some cases, using a Set or an array can have significant performance effects on certain operations, like searching, insertion, or deletion. For example: * Searching for an element in a Set typically has a time complexity of O(1), making it faster than searching in an array (which is often O(n)). * Inserting or deleting elements in a Set usually happens in constant time, whereas doing so in an array might require shifting all subsequent elements. **Alternatives** Other alternatives for creating arrays from iterables include: * Using `forEach()` and concatenating the results: `(...).map(x => [...x]).concat([...])` * Using a `for` loop or `while` loop to iterate over the iterable and push elements into a new array * Utilizing other libraries or frameworks that provide optimized implementations for these operations (e.g., Lodash's `arrayFrom()` function) However, using built-in methods like `Array.from()` or the spread operator (`...`) is often the most efficient and convenient approach.
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