Benchmark: Undefine vs Delete

Tests:

Undefine
obj = { fn: function() { return 7; } }; obj.fn = undefined;
Delete
obj = { fn: function() { return 7; } }; delete obj.fn;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Undefine
Delete

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 6 years ago)

User agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.181 Safari/537.36

Browser/OS: Chrome 66 on Windows 7

View result in a separate tab

Test name	Executions per second
Undefine	1009603.2 Ops/sec
Delete	1353960.2 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the explanation of the provided benchmark.

**What is being tested?**

The benchmark measures the performance difference between two approaches: defining a function as `undefined` and deleting it, respectively.

**Options compared:**

There are only two options being compared:

1. **Undefining a function**: This approach involves assigning `undefined` to a function property. In JavaScript, `undefined` is a valid value that can be assigned to a variable or property.
2. **Deleting a function**: This approach involves using the `delete` operator to remove a function from an object.

**Pros and cons of each approach:**

1. **Undefining a function**:
	* Pros:
		+ Can be faster, as it doesn't require a memory allocation or deallocation.
		+ May have better cache locality, as the `undefined` value is more compact than a deleted property.
	* Cons:
		+ May not work correctly in some browsers or environments that have issues with `undefined` properties.
2. **Deleting a function**:
	* Pros:
		+ Works consistently across all browsers and environments.
		+ Can be useful for removing functions from objects, as it doesn't leave behind any `undefined` properties.
	* Cons:
		+ May require additional memory allocation or deallocation, which can impact performance.

**Library usage:**

None of the provided benchmark code uses any external libraries.

**Special JS feature or syntax:**

The benchmark uses a feature specific to JavaScript, namely the use of the `delete` operator to remove properties from objects.

**Other alternatives:**

If deleting a function is not an option, other approaches can be used:

1. **Reassigning to null**: Assigning the deleted property to `null` would achieve similar results to deletion.
2. **Using a proxy**: Creating a proxy object with a `deleteProperty` handler can remove properties from objects without using the `delete` operator.
3. **Using a library function**: Depending on the specific requirements, other libraries or frameworks might provide functions for removing properties from objects.

**Benchmark preparation code:**

The provided script preparation code simply defines an object `obj` with a function property `fn`, and then undefines (or deletes) the `fn` property using either of the two approaches. The code does not perform any additional setup or initialization that would impact the benchmark results.

In summary, this benchmark measures the performance difference between two approaches to removing properties from objects: defining a function as `undefined` and deleting it. While both approaches have their pros and cons, deletion is generally considered more reliable and consistent across all browsers and environments.

Related benchmarks:

Undefine vs Delete (version: 0)

Comparing performance of: Undefine vs Delete

Created: 7 years ago by: Guest

Jump to the latest result

Undefine

Delete

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):