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fromEntries vs reduce
(version: 0)
Comparing performance of:
fromEntries vs reduce
Created:
4 years ago
by:
Guest
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Tests:
fromEntries
const a = Array.from(Array(10000).keys()) const arr = a.map(item => [item, item]) const obj = Object.fromEntries(arr);
reduce
const a = Array.from(Array(10000).keys()) const arr = a.map(item => [item, item]) const obj2 = arr.reduce((acc, curr) => { return { ...acc, [curr[0]] : curr[1] } }, {})
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Suite status:
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Test case name
Result
fromEntries
reduce
Fastest:
N/A
Slowest:
N/A
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the provided benchmark and explain what is being tested. **Benchmark Definition JSON** The benchmark definition JSON specifies two individual test cases: 1. `fromEntries` 2. `reduce` **Options Compared** In this benchmark, we have two options for creating an object from an array of key-value pairs: a. **`Object.fromEntries()`**: This method is a modern JavaScript feature introduced in ECMAScript 2017 (ES7). It allows you to create an object by passing an iterable of key-value pairs. b. **`Array.prototype.reduce()`**: This method is a built-in array method that applies a callback function to each element in the array and returns a new value. In this case, we're using it to merge an array of objects into a single object. **Pros and Cons** * **`Object.fromEntries()`**: + Pros: concise and readable syntax, efficient (fast), widely supported across modern browsers. + Cons: may not be supported in older browsers or environments that don't have ES7 support. Additionally, it only works with arrays of key-value pairs; if you need to merge objects with a more complex structure, this method might not work as expected. * **`Array.prototype.reduce()`**: + Pros: widely supported across all JavaScript environments (even older browsers), can handle any iterable input. However, the code can be less readable and more verbose than using `Object.fromEntries()`. + Cons: slower performance compared to `Object.fromEntries()` for simple transformations. **Library Usage** In neither of the test cases is a library explicitly mentioned. Both methods rely on built-in JavaScript functionality. **Special JS Features/Syntax** There are no special JavaScript features or syntax used in these benchmarks. They use standard ECMAScript 2017 (ES7) language features. **Other Considerations** When to use each method: * Use `Object.fromEntries()` when you need a simple, efficient way to create an object from an array of key-value pairs and can afford the modern JavaScript syntax. * Use `Array.prototype.reduce()` when working with older browsers or environments that don't support ES7 features, or if you need more control over the merging process. **Alternative Approaches** Other alternatives for creating objects from arrays include: 1. **`Object.assign()`**: While not as efficient as `Object.fromEntries()`, it can be used to merge objects by passing an array of key-value pairs. 2. **Manual object creation using a loop**: You can use a simple loop to create an object by iterating over the array and assigning values manually. However, these alternatives are generally less efficient and less readable than using `Object.fromEntries()` or `Array.prototype.reduce()`.
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