Benchmark: object.keys map vs for in

Tests:

for in
const list = [] const data = { 1: '100', 2: '200', 3: '300' } for (const key in data) { list.push({ value: key, name: data }) }
object.keys map
const data = { 1: '100', 2: '200', 3: '300' } const list = Object.keys(data).map(it => ({ value: it, name: data[it] }))

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for in
object.keys map

Fastest: N/A

Slowest: N/A

Latest run results:

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Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark JSON and explain what's being tested.

**Benchmark Definition**

The benchmark is defined by two test cases: `object.keys map` and `for in`. These two approaches are used to iterate over an object's keys and extract values.

**Options Compared**

The two options being compared are:

1. **Object.keys() + Array.prototype.map()**: This approach uses the `Object.keys()` method to get an array of the object's keys, and then uses `Array.prototype.map()` to create a new array with the desired output (key-value pairs).
2. **For...in loop**: This approach uses a traditional `for...in` loop to iterate over the object's keys.

**Pros and Cons**

**Object.keys() + Array.prototype.map():**

Pros:

* More concise and readable code
* Less prone to errors due to the explicit iteration process

Cons:

* May incur additional overhead due to the creation of an intermediate array
* Requires JavaScript version support (not available in older browsers)

**For...in loop:**

Pros:

* Can be more efficient in older browsers or environments with limited JavaScript features
* Does not require creating an intermediate array

Cons:

* More prone to errors due to the implicit iteration process
* Code can become less readable and more verbose

In general, for modern JavaScript applications with good browser support, the `Object.keys() + Array.prototype.map()` approach is preferred. However, in older browsers or environments, the `For...in loop` approach may be necessary.

**Library and Purpose**

None of the test cases use any external libraries.

**Special JS Feature or Syntax**

The benchmark uses modern JavaScript features, such as arrow functions (`it => ({ value: key, name: data })`) and template literals (`data[it]`). These features are widely supported in modern browsers but may not be available in older versions. If you need to support older browsers, you may need to use polyfills or transpile the code.

**Other Alternatives**

If you're looking for alternative approaches to iterate over an object's keys, consider using:

* `for...in` loop (as mentioned earlier)
* `Object.entries()` and `Array.prototype.map()`: This approach uses the `Object.entries()` method to get an array of key-value pairs and then uses `Array.prototype.map()` to create a new array with the desired output.

For example:
```javascript
const list = Object.entries(data).map(([key, value]) => ({ value: key, name: value }));
```
This approach is similar to the `Object.keys() + Array.prototype.map()` approach but avoids using the `Object.keys()` method. Instead, it uses the `Object.entries()` method to get an array of key-value pairs.

Keep in mind that these alternatives may have slightly different performance characteristics or code readability compared to the original approaches.

Related benchmarks:

object.keys map vs for in (version: 0)

Comparing performance of: for in vs object.keys map

Created: 4 years ago by: Registered User

Jump to the latest result

for in

object.keys map

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):