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Array.from vs Spread using Map
(version: 0)
Comparing performance of:
Array.from vs Spread
Created:
5 years ago
by:
Guest
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Tests:
Array.from
var fooSet = new Map(); for(var i=0;i<100;i++) { fooSet.set(i, i); } var other = Array.from(fooSet);
Spread
var fooSet = new Map(); for(var i=0;i<100;i++) { fooSet.set(i, i); } var other = [...fooSet.entries()];
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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):
**What is being tested?** The provided benchmark measures the performance difference between two approaches to convert a Map to an array using JavaScript. In the first test case, `Array.from(fooSet)`, an existing Map object `fooSet` is passed to the `Array.from()` method. This approach creates a new array by iterating over the key-value pairs of the map and adding them as individual elements to the array. In the second test case, `...fooSet.entries()`, an existing Map object `fooSet` is spread using the syntax `[...fooSet.entries()]`. This approach creates a new array by spreading the key-value pairs of the map into separate elements of the array. **Options being compared** The two options being compared are: 1. **Array.from()**: Creates a new array by iterating over the key-value pairs of the map and adding them as individual elements to the array. 2. **Spread operator with entries()**: Creates a new array by spreading the key-value pairs of the map into separate elements of the array. **Pros and Cons** * **Array.from()**: + Pros: Can handle cases where Map has different types of keys (including strings, numbers, symbols), can be more efficient for large maps. + Cons: May have overhead due to function call and iteration, may not perform well for very small maps. * **Spread operator with entries()**: + Pros: Can be more efficient for very small maps, can handle cases where Map has different types of keys (including strings, numbers, symbols), does not require a separate `Map` object creation. + Cons: May have overhead due to spread operator and method call, may not perform well for large maps. **Library and purpose** The `Map` data structure is a built-in JavaScript library that provides a way to store key-value pairs in an unordered collection. In this benchmark, the `Map` object is used as input for both test cases. **Special JS feature or syntax** The spread operator (`...`) is a special syntax introduced in ECMAScript 2015 (ES6) that allows you to expand array-like objects into new arrays. The `entries()` method returns an iterator over the key-value pairs of the map, which can be iterated over using the spread operator. **Other alternatives** Alternative approaches to convert a Map to an array include: * Using the `Array.from()` method with a custom callback function to extract the values from the map. * Using a library like Lodash's `mapValues()` function. * Using a DOM-based approach, such as iterating over the key-value pairs of the map using a for loop and then constructing an HTML element array. However, these alternatives may not be as efficient or elegant as the options being compared in this benchmark.
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