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for-in vs for object.keys keys
(version: 0)
Comparing performance of:
for-in vs Object.keys
Created:
4 years ago
by:
Guest
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Script Preparation code:
var obj = { 'a': 1, 'b': 1, 'c': 1, 'd': 1, 'e': 1, 'f': 1, 'g': 1 };
Tests:
for-in
for (var key in obj) { console.log(key); }
Object.keys
const keys = Object.keys(obj) for(let i= 0; i< keys.length; i++){ console.log(keys[i]) }
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
for-in
Object.keys
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 what is being tested in this benchmark. **Benchmark Definition** The benchmark compares the performance of two approaches to iterate over an object: 1. `for-in` loop 2. Using the `Object.keys()` method and iterating over its result using a traditional `for` loop. **Options Compared** * `for-in` loop: This approach uses the `in` operator to iterate over the object's property names. * Object.keys() + Traditional for loop: This approach uses the `Object.keys()` method to get an array of the object's property names, and then iterates over this array using a traditional `for` loop. **Pros and Cons** * **For-in loop**: + Pros: Simple and straightforward, no need to worry about array indexing or bounds checking. + Cons: Can be slower due to the overhead of iterating over the object's property names, which may involve searching for properties. Additionally, `for-in` loops can iterate over inherited properties, which might not be desirable in all cases. * Object.keys() + Traditional for loop: + Pros: Faster and more predictable than the `for-in` loop, as it avoids iterating over inherited properties and uses array indexing (which is typically faster). + Cons: Requires extra memory to store the result of `Object.keys()`, which can be a concern for large objects. **Library/Functionality** * `Object.keys()` method: This is a built-in JavaScript function that returns an array of the object's property names. It was introduced in ECMAScript 2015 (ES6). **Special JS Features/Syntax** None mentioned explicitly, but keep in mind that both approaches work on modern browsers and most JavaScript environments. **Other Alternatives** * Using `for...in` with the `Object.getOwnPropertyNames()` method instead of `Object.keys()`. This would iterate over both own properties and inherited ones. * Using a library like Lodash's `keys()` function or Underscore.js's `keys()` function, which might provide additional functionality or optimizations. In summary, this benchmark is testing two approaches to iterate over an object: the traditional `for-in` loop and using the `Object.keys()` method with a traditional for loop. The results will show which approach performs better in terms of execution speed.
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