Benchmark: delete vs forEach

Script Preparation code:

var original = {one: 1, two: 2, three: 3, four: 4, five: 5, six: 6}
var keptKeys = ['one', 'three', 'five']

Tests:

delete
var deleteCopy = Object.assign({}, original) delete deleteCopy.two delete deleteCopy.four delete deleteCopy.six
foreach
var copy = {} for (let key in original) { if (keptKeys.indexOf(key) > -1) { copy[key] = original[key] } }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
delete
foreach

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

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

**Benchmark Overview**

The benchmark compares two approaches for deleting properties from an object: `delete` and `forEach`. The goal is to measure which approach is faster, more efficient, and potentially more reliable.

**Options Compared**

There are two options compared:

1. **Delete**: This approach uses the `delete` keyword to delete properties directly from the object. It's a simple and straightforward way to remove properties.
2. **ForEach**: This approach uses a `for...in` loop with `keptKeys.indexOf(key) > -1` to filter and delete properties. It's more explicit and might be considered more robust, but also slightly slower.

**Pros and Cons of Each Approach**

**Delete**:

Pros:

* Simple and concise syntax
* Fast execution

Cons:

* Might not work as expected if the `delete` keyword is overridden or if the object has other properties with the same name.
* Does not provide any feedback on which property was deleted (if any).

**ForEach**:

Pros:

* More explicit and potentially more reliable
* Provides feedback on which property was deleted

Cons:

* Slightly slower execution compared to `delete`
* Requires a loop and conditional checks, making it slightly less concise.

**Library Usage**

None of the provided benchmark code uses external libraries. However, the `Object.assign()` function is used in the `Delete` test case, which is a built-in JavaScript method for creating a shallow copy of an object.

**Special JS Features or Syntax**

The benchmark does not explicitly use any special JavaScript features or syntax that would be unique to specific browsers or versions. It focuses on core JavaScript concepts and standard library functions.

**Other Alternatives**

If you want to explore other approaches, here are some alternatives:

* Use a more explicit delete approach using `delete obj.prop` instead of just `delete obj.prop`.
* Use a different data structure, such as an array, to store the properties to be deleted.
* Use a third-party library or framework that provides optimized property deletion functions.

**Benchmark Preparation Code**

The provided script preparation code creates two objects: `original` with six properties and `keptKeys` with three properties (`one`, `three`, and `five`). These objects are then used in the benchmark test cases to simulate a real-world scenario where you need to delete specific properties from an object.

**Individual Test Cases**

There are two test cases:

1. **Delete**: This test case uses the `delete` keyword to delete properties directly from the `original` object.
2. **ForEach**: This test case uses a `for...in` loop with `keptKeys.indexOf(key) > -1` to filter and delete properties from the `original` object.

These test cases are designed to measure the performance difference between using `delete` versus iterating through an array of keys to remove them from the object.

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/94.0.4606.81 Safari/537.36

Browser/OS: Chrome 94 on Windows

View result in a separate tab

Test name	Executions per second
delete	1115165.5 Ops/sec
foreach	857660.3 Ops/sec

Related benchmarks:

delete vs forEach (version: 0)

Comparing performance of: delete vs foreach

Created: 7 years ago by: Guest

Jump to the latest result

delete

foreach

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):