Toggle navigation
MeasureThat.net
Create a benchmark
Tools
Feedback
FAQ
Register
Log In
Object.keys().forEach() vs for in
(version: 0)
Comparing performance of:
Object.keys vs for in
Created:
6 years ago
by:
Guest
Jump to the latest result
Tests:
Object.keys
const simpleObject = {a: 'a', b: 'b', 1: 1, 2: 2, longProp: 'longProp'}; let index = 0; Object.keys(simpleObject).forEach(propValue => ++index);
for in
const simpleObject = {a: 'a', b: 'b', 1: 1, 2: 2, longProp: 'longProp'}; let index = 0; for(const prop in simpleObject) { ++index; }
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
Fork
Test case name
Result
Object.keys
for in
Fastest:
N/A
Slowest:
N/A
Latest run results:
No previous run results
This benchmark does not have any results yet. Be the first one
to run it!
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the provided JSON and explain what's being tested. **Benchmark Definition** The benchmark is comparing two JavaScript methods: `Object.keys().forEach()` and `for in`. These two approaches are used to iterate over an object's properties. **Options Compared** The benchmark is testing the performance of: 1. **`Object.keys().forEach()`**: This method uses the `Array.prototype.forEach()` function to iterate over the object's keys (property names). It returns a new array containing the property names. 2. **`for in`**: This is an older approach to iterating over an object's properties, which uses a traditional `for` loop with the `in` keyword. **Pros and Cons** * `Object.keys().forEach()`: * Pros: Modern, efficient, and concise way of iterating over objects. It returns a new array containing the property names, allowing for easy iteration without modifying the original object. * Cons: Creates an additional array, which might not be necessary for every use case. * `for in`: * Pros: Wide browser support, can be used with older JavaScript versions (before ECMAScript 2015). However, it modifies the original object by adding new properties (`__proto__`) to its prototype chain. * Cons: Less efficient and less concise compared to `Object.keys().forEach()`. It also has limitations when dealing with certain types of objects (e.g., arrays). **Library/Feature Used** Neither `Object.keys().forEach()` nor `for in` relies on any external libraries. They are built-in JavaScript features. **Special JS Feature/Syntax** The benchmark uses the following feature: * **Arrow functions**: The `propValue => ++index` syntax is an example of using arrow functions (introduced in ECMAScript 2015) to define small, anonymous functions. * Pros: Concise way of defining small functions. More readable and maintainable than traditional function declarations or event handlers with `function() { ... }`. * Cons: Not supported by older browsers. **Other Alternatives** If you need to iterate over an object's properties and want a more efficient solution, consider using: * **`Object.entries()`**: Returns an array of key-value pairs. If you only need the keys or values, use `Object.keys()` or `Object.values()`, respectively. * **`for...of` loop**: Similar to `for in`, but allows iterating over arrays and other iterable objects. **Benchmark Preparation Code** The provided script preparation code is empty (`"Script Preparation Code": null`). It's expected that the test user will add their own JavaScript code to prepare for the benchmark.
Related benchmarks:
For in vs For of
For in vs Object.*.forEach
For in vs Object.keys for loop vs Object.keys.forEach
Array.forEach vs Object.keys().forEach
Object iteration for-in vs object.keys
Comments
Confirm delete:
Do you really want to delete benchmark?