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make map with entries vs for of
(version: 0)
Comparing performance of:
map with entries vs map with for of
Created:
3 years ago
by:
Guest
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Script Preparation code:
var arr = Array.from({length: 1000000}).map((_,i)=>({id: i}));
Tests:
map with entries
new Map(arr.entries())
map with for of
const m = new Map(); for (let item in arr) { m.set(item.id, item); }
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
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Test case name
Result
map with entries
map with for of
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 JavaScript microbenchmark on MeasureThat.net. **Benchmark Definition** The benchmark definition is provided in JSON format, which represents two test cases: 1. Creating a Map from an array using `Map.entries()` 2. Creating a Map from an array using a traditional `for...in` loop and `set()` method These two approaches are being compared to measure their performance. **Options Compared** The two options being compared are: * **Map.entries()**: This method creates a new Map instance from the entries of another iterable (in this case, the `arr` array). It's a concise way to create a Map with key-value pairs. * **Traditional for...in loop and set() method**: This approach uses a traditional `for...in` loop to iterate over the array elements and sets each element as a key-value pair in the Map instance. **Pros and Cons of Each Approach** **Map.entries():** Pros: * Concise and expressive syntax * Fast and efficient, since it leverages the underlying iterable's iteration logic Cons: * May have performance overhead due to the creation of an intermediate iterator object * Limited control over iteration order (since it follows the underlying iterable's order) **Traditional for...in loop and set() method:** Pros: * Provides fine-grained control over iteration order * Can be more flexible when working with complex data structures Cons: * More verbose syntax, which can make code harder to read and maintain * May have performance overhead due to the explicit looping logic **Library Used** None explicitly mentioned in this benchmark. However, it's worth noting that both `Map.entries()` and traditional `for...in` loops rely on internal browser libraries or engine optimizations. **Special JavaScript Features/Syntax** No special features or syntax are used in these test cases. The focus is solely on comparing the performance of two basic Map creation approaches. **Other Alternatives** If you're interested in exploring alternative approaches, here are a few: * Using `Array.prototype.reduce()` to create a Map: `const m = arr.reduce((map, item) => map.set(item.id, item), new Map());` * Using `reduce()` with an accumulator function and `set()` method: `const m = arr.reduce((m, item) => { m.set(item.id, item); return m; }, new Map());` Keep in mind that these alternatives may have different performance characteristics or trade-offs compared to the original approaches.
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