Benchmark: test: loop vs keys

Script Preparation code:

var ob = {
    a: '1',
    b: '2'
};
var number = 0;

Tests:

for
for(const key in ob) { number += 1; }
keys
Object.keys(ob).forEach(key => { number += 1; });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for
keys

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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

LLMs can make mistakes. Check important info.

I'd be happy to explain the benchmark and its various components.

**Benchmark Overview**

The provided JSON represents a JavaScript microbenchmark created on MeasureThat.net. The benchmark compares two approaches for iterating over an object's keys: the traditional `for` loop and the `Object.keys()` method with a `forEach()` callback.

**Script Preparation Code**

The script preparation code defines two variables:
```javascript
var ob = {
  a: '1',
  b: '2'
};

var number = 0;
```
Here, `ob` is an object literal containing two properties (`a` and `b`) with string values. The variable `number` is initialized to zero.

**Html Preparation Code**

The HTML preparation code is empty, which means the benchmark doesn't rely on any specific HTML structure or layout.

**Benchmark Test Cases**

There are two test cases:

1. **"for"`**: This test case uses a traditional `for` loop to iterate over the object's keys.
```javascript
for (const key in ob) {
  number += 1;
}
```
This approach is simple and widely supported, but it can be slower than other methods due to the overhead of checking each property using `in`.

2. **"keys"`**: This test case uses the `Object.keys()` method with a `forEach()` callback to iterate over the object's keys.
```javascript
Object.keys(ob).forEach(key => {
  number += 1;
});
```
This approach is often faster than the traditional `for` loop because it avoids the overhead of checking each property using `in`.

**Library: None**

There are no external libraries used in this benchmark.

**Special JS Features/Syntax: None**

Neither of these test cases uses any special JavaScript features or syntax that would require additional explanation.

**Other Alternatives**

Other approaches to iterating over an object's keys include:

* Using the `for...in` loop with a custom iterator (not shown in this benchmark)
* Using a `Map` or `Set` instead of an object (not shown in this benchmark)
* Using a library like Lodash or Ramda, which provides more advanced iteration utilities (not applicable in this case)

**Pros and Cons**

Here's a brief summary of the pros and cons of each approach:

* Traditional `for` loop:
	+ Pros: Wide support, simple to implement.
	+ Cons: Can be slower than other methods due to property checking overhead.
* `Object.keys()` with `forEach()`:
	+ Pros: Often faster than traditional `for` loop, eliminates property checking overhead.
	+ Cons: Requires modern JavaScript features (ECMAScript 5 or later), may not work in older browsers.

The benchmark result shows the execution time per second for each test case on a specific browser and device platform. The "for" loop performs slightly better than the `keys` approach, but both are relatively fast due to the simplicity of the iteration logic.

Related benchmarks:

test: loop vs keys (version: 0)

Comparing performance of: for vs keys

Created: 5 years ago by: Guest

Jump to the latest result

for

keys

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):