Benchmark: Delete vs Setting undefined

Script Preparation code:

window.data = {key: 'value'}

Tests:

Undefined
window.data.key = undefined
Delete
delete window.data.key

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Undefined
Delete

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:134.0) Gecko/20100101 Firefox/134.0

Browser/OS: Firefox 134 on Linux

View result in a separate tab

Test name	Executions per second
Undefined	4842714.0 Ops/sec
Delete	4815648.5 Ops/sec

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 definition and test cases to understand what is being tested.

**Benchmark Definition:**

The benchmark is comparing two approaches for removing properties from an object:

1. **Setting undefined**: Setting a property to `undefined` will effectively remove it from the object, as objects in JavaScript do not store values when their keys are set to `undefined`.
2. **Delete**: The `delete` operator is used to remove a property from an object.

**Options Compared:**

The benchmark is comparing two options:

* Setting a property to `undefined`
* Using the `delete` operator

**Pros and Cons of Each Approach:**

* **Setting undefined**:
	+ Pros:
		- Generally faster, as it doesn't require a special operation.
		- Can be used for other purposes beyond removing properties (e.g., setting default values).
	+ Cons:
		- May not work correctly in certain situations, such as when the property is part of an array or object with complex inheritance.
* **Delete**:
	+ Pros:
		- Works correctly in most situations and is widely supported.
	+ Cons:
		- Can be slower than setting to `undefined`, especially for large objects.

**Other Considerations:**

When using `delete` to remove properties, it's essential to note that:

* The property must exist on the object before calling `delete`.
* If you're removing a property from an array or object with complex inheritance, it may affect other parts of the object.
* Some older browsers might not support `delete`.

**Library Usage:**

There is no library used in this benchmark definition.

**Special JS Feature/Syntax:**

None mentioned.

**Benchmark Preparation Code:**

The script preparation code sets up a global variable `window.data` with a property `key`, which is then modified to set it to either `undefined` or use the `delete` operator.

**Individual Test Cases:**

Each test case measures the execution time of one approach:

* **Undefined**: Measures setting the property to `undefined`.
* **Delete**: Measures using the `delete` operator.

The benchmark runs both tests multiple times and reports the average execution time per second for each test case. The raw UAStrings, browser, device platform, operating system, and executions per second are also reported.

**Other Alternatives:**

If you want to optimize removal of properties in your code, consider using:

* `Object.keys()` and `forEach()` to iterate over the object's keys and delete them individually.
* `for...in` loop to iterate over the object's property names and use `delete` or `set` accordingly.
* Using a library like Lodash or Underscore.js for more complex object manipulation.

In summary, this benchmark compares two approaches for removing properties from an object: setting it to `undefined` versus using the `delete` operator. The results will help you understand which approach is faster and more reliable in your specific use cases.

Related benchmarks:

Delete vs Setting undefined (version: 0)

Comparing performance of: Undefined vs Delete

Created: 3 years ago by: Guest

Jump to the latest result

Undefined

Delete

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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