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for in vs. Object.keys vs Object.entries v2
(version: 3)
Comparing performance of:
for in vs Object.keys vs Object.entries
Created:
3 years ago
by:
Registered User
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Script Preparation code:
var searchCondition = {brandName: 'samsung', displayCategoryNumber: 123, searchKeyword: '갤럭시'};
Tests:
for in
var temp = []; for (var prop in searchCondition) { temp.push({ [prop]: searchCondition[prop] }) } console.log(temp);
Object.keys
var temp = Object.keys(searchCondition).map(prop => { return { [prop]: searchCondition[prop] }; }); console.log(temp);
Object.entries
var temp = Object.entries(searchCondition).map(([prop, value])=> { return { [prop]: value }; }); console.log(temp);
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (3)
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Test case name
Result
for in
Object.keys
Object.entries
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 measures the performance difference between three approaches to iterate over an object: 1. `for in` 2. `Object.keys` 3. `Object.entries` (v2) Each approach is tested on a simple search condition object, which we'll break down later. **Approaches Compared** ### 1. `for in` This method uses the `for in` loop to iterate over the object's properties. The `in` keyword returns an iterator that yields each property name, allowing us to access both the property name and value using the bracket notation (`searchCondition[prop]`). Pros: * Easy to understand and implement * Works well for simple objects with few properties Cons: * Performance can be slower due to the overhead of iterating over properties * Not suitable for large or deeply nested objects ### 2. `Object.keys` This method uses the `Object.keys()` function to get an array of property names, which we can then iterate over using the `map()` function. Pros: * Fast and efficient, as it only returns a few properties at a time * Works well for large or deeply nested objects Cons: * May require additional memory allocation for the map output * Can be slower due to the overhead of parsing property names ### 3. `Object.entries` (v2) This method uses the `Object.entries()` function to get an array of key-value pairs, which we can then iterate over using the `map()` function. Pros: * Fast and efficient, as it only returns a few properties at a time * Works well for large or deeply nested objects Cons: * Requires modern JavaScript versions (ECMAScript 2015+) to work properly * May not be supported by older browsers or environments **Library and Special Features** In the benchmark code, we see that `Object.entries` is used in version 2 (v2). This is a special feature introduced in ECMAScript 2015+, which allows us to get an array of key-value pairs from an object. Other libraries or features are not used in this benchmark. **Considerations** When choosing between these approaches, consider the following factors: * Performance: `Object.keys` and `Object.entries` (v2) tend to be faster than `for in`, especially for large objects. * Memory usage: `Object.keys` may require more memory allocation due to the map output. * Browser support: Ensure that your target browsers support modern JavaScript features. **Alternatives** If you need alternative approaches, consider the following: * Using `forEach()` method instead of `map()`: This can provide similar performance benefits without requiring additional function creation. * Using `reduce()` method: This can be a more concise and expressive way to iterate over objects, but may have different performance characteristics. However, these alternatives are not part of the original benchmark code and would require additional modifications to test their performance.
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