Benchmark: delete vs set - MeasureThat.net

Script Preparation code:

x = { a: 'test' }

Tests:

delete
delete x.a
set
x.a = undefined

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
delete
set

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:80.0) Gecko/20100101 Firefox/80.0

Browser/OS: Firefox 80 on Windows

View result in a separate tab

Test name	Executions per second
delete	18118612.0 Ops/sec
set	83684024.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided JSON data and explain what's being tested in this JavaScript microbenchmark.

**Benchmark Definition**

The benchmark is defined by a single JSON object with two properties:

* `Name`: a string that uniquely identifies the benchmark, which is "delete vs set" in this case.
* `Description`: an empty string, indicating that no descriptive text is provided for this benchmark.
* `Script Preparation Code`: a JavaScript code snippet that creates an object `x` with a single property `a` and assigns it a string value `'test'`.
* `Html Preparation Code`: an empty string, indicating that no HTML code needs to be prepared for this benchmark.

**Individual Test Cases**

The benchmark consists of two test cases, each defined in a separate JSON object:

1. The first test case has the following properties:
	* `Benchmark Definition`: a single line of JavaScript code that deletes the property `a` from the `x` object, `delete x.a`.
	* `Test Name`: the string "delete".
2. The second test case has the following properties:
	* `Benchmark Definition`: another single line of JavaScript code that assigns an undefined value to the property `a` of the `x` object, `x.a = undefined`.
	* `Test Name`: the string "set".

**What's being tested**

The benchmark is testing the performance difference between two approaches:

1. **Deleting a property**: The first test case (`delete x.a`) tests how fast JavaScript can delete a property from an object.
2. **Assigning an undefined value**: The second test case (`x.a = undefined`) tests how fast JavaScript can assign an undefined value to a property of an object.

**Options compared**

The benchmark is comparing the performance of these two approaches:

1. `delete x.a` (property deletion)
2. `x.a = undefined` (assigning an undefined value)

**Pros and Cons of each approach**

Here are some pros and cons of each approach:

* **Property deletion (`delete x.a`)**:
	+ Pros:
		- Can be faster since it doesn't involve creating a new object or modifying the existing one.
		- May be more cache-friendly, as it only involves deleting a property without creating a new reference.
	+ Cons:
		- Can lead to unnecessary work being done by the garbage collector, which may slow down other parts of the program.
* **Assigning an undefined value (`x.a = undefined`)**:
	+ Pros:
		- Avoids potential issues with deleting properties, which can be tricky in certain scenarios (e.g., when working with objects that have multiple levels of inheritance).
	+ Cons:
		- May involve more work since it requires creating a new property reference and setting its value to undefined.

**Other considerations**

* The benchmark assumes that the object `x` is not modified elsewhere in the program, which might affect the performance results.
* The benchmark only tests deletion and assignment of properties with a specific data type (string), which might limit the applicability of the results.
* Other factors like the browser's garbage collection algorithm, caching behavior, and optimization techniques can influence the performance results.

**Alternative approaches**

There are other ways to delete or modify properties in JavaScript:

* Using bracket notation (`x['a'] = undefined`): This approach is similar to assigning an undefined value using dot notation but uses bracket notation to access the property.
* Using a for...in loop (`for (var key in x) { if (key === 'a') { delete x[key]; } } ```: This approach iterates over all properties of the object and deletes the specific one.

Keep in mind that these alternative approaches might have different performance characteristics or implications, depending on the specific use case.

Related benchmarks:

delete vs set (version: 0)

Comparing performance of: delete vs set

Created: 4 years ago by: Guest

Jump to the latest result

delete

set

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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