Benchmark: For in vs Object.*.forEach vs Object.values with equal usage

Script Preparation code:

var obj = new Object()
var keys = (new Array(10000)).fill(0).map((x, i) => { return i + 1 })
keys.forEach((x) => { obj['prop' + x] = x })

Tests:

For In
for (const key in obj) { console.log(key, obj[key]); }
Object values
for(let value of Object.values(obj)){ console.log(value); }
Object keys forEach
Object.keys(obj).forEach(key => console.log(key, obj[key]));
Object entries forEach
Object.entries(obj).forEach(([key, value]) => console.log(key, value));
object values forEach
Object.values(obj).forEach(value => console.log(value));

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
For In
Object values
Object keys forEach
Object entries forEach
object values forEach

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the benchmark and explore what's being tested.

**Benchmark Definition**

The benchmark definition is a JSON object that defines the test case. It contains a script preparation code, which sets up an object with 10 properties ( keys ) using the `for...in` loop. The prepared HTML is empty, indicating that no HTML-related tests are performed.

In this benchmark, four different approaches are being compared:

1. **For In**: This approach uses the `for...in` loop to iterate over the object's properties.
2. **Object values**: This approach uses `Object.values()` to get an array of the object's property values.
3. **Object keys forEach**: This approach uses `Object.keys()` and `forEach()` to iterate over the object's property names.
4. **Object entries forEach**: This approach uses `Object.entries()` and `forEach()` to iterate over the object's key-value pairs.

**Options Compared**

The four approaches are compared in terms of their performance, specifically:

* How many executions per second (ExecutionsPerSecond) each approach can achieve.

**Pros and Cons**

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

1. **For In**:
	* Pros: Simple and widely supported; no additional library or module needed.
	* Cons: May not be as efficient as other approaches, especially for large objects.
2. **Object values**:
	* Pros: Efficient and widely supported; uses the `Object.values()` method, which is relatively fast.
	* Cons: Requires a modern browser that supports `Object.values()`.
3. **Object keys forEach**:
	* Pros: Fast and efficient; uses `forEach()` to iterate over the property names.
	* Cons: May not be as widely supported as other approaches, especially older browsers.
4. **Object entries forEach**:
	* Pros: Efficient and unique approach that iterates over key-value pairs.
	* Cons: Less widely supported than other approaches; requires a modern browser that supports `Object.entries()`.

**Libraries and Features**

None of the approaches rely on specific libraries or modules, except for:

* **Object.values()**: This method is part of the ECMAScript standard, so all modern browsers support it.
* **Object.keys()**: Also part of the ECMAScript standard, but some older browsers may not support it.

**Special JS Features**

There are no special JavaScript features or syntax used in this benchmark. All approaches use standard ECMAScript syntax.

**Alternatives**

Other alternatives to these approaches might include:

* Using a library like `lodash` that provides an efficient way to iterate over objects.
* Using a framework like React or Angular, which provide built-in support for iterating over objects and arrays.
* Implementing custom iteration logic using a different approach, such as using a custom iterator or a loop.

Keep in mind that the best approach will depend on the specific use case and requirements. This benchmark aims to provide a general comparison of four common approaches to iterating over objects in JavaScript.

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/97.0.4692.71 Safari/537.36

Browser/OS: Chrome 97 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
For In	8.3 Ops/sec
Object values	8.7 Ops/sec
Object keys forEach	7.4 Ops/sec
Object entries forEach	6.8 Ops/sec
object values forEach	9.2 Ops/sec

Related benchmarks:

For in vs Object.*.forEach vs Object.values with equal usage (version: 0)

Comparing performance of: For In vs Object values vs Object keys forEach vs Object entries forEach vs object values forEach

Created: 2 years ago by: Guest

Jump to the latest result

For In

Object values

Object keys forEach

Object entries forEach

object values forEach

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):