Benchmark: delete vs null vs undefined vs void 0 vs Object.create(null) propertie

Tests:

null
for(let i = 0; i < 1000;i++) { let a = { a: 999, b: 3000 } a.a = null; a.b = null; }
undefined
for(var i = 0; i < 1000;i++) { let a = { a: 999, b: 3000 } a.a = undefined; a.b = undefined; }
delete
for(var i = 0; i < 1000;i++) { let a = { a: 999, b: 3000 } delete a.a; delete a.b; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
null
undefined
delete

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 8 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/137.0.0.0 Safari/537.36

Browser/OS: Chrome 137 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
null	2967382.8 Ops/sec
undefined	1002510.2 Ops/sec
delete	12675.3 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the provided JSON and explain what's being tested, the options being compared, pros and cons of each approach, and other considerations.

**Benchmark Definition**

The benchmark is testing the performance of different ways to set a property to null, undefined, or delete it in JavaScript. The test case is creating an object with two properties: `a` and `b`, which are initialized with values of 999 and 3000, respectively.

There are four test cases:

1. Setting a property to `null`.
2. Setting a property to `undefined`.
3. Deleting a property.
4. Creating an object using `Object.create(null)`.

**Script Preparation Code**

Each test case has its own script preparation code, which is empty in this case (`"Script Preparation Code": null`). This means that no specific setup or initialization code is required before running the benchmark.

**Individual Test Cases**

The three individual test cases are:

1. **null**: Sets `a.a` and `a.b` to `null`.
2. **undefined**: Sets `a.a` and `b` (note: this uses a different property) to `undefined`.
3. **delete**: Deletes the existence of `a.a` and `b`.

**Problems with the current approaches**

The current approach has several issues:

* Using `a = { ... }` is not recommended as it creates a new object every time, leading to unnecessary allocations.
* Using `for` loops is not optimized for performance.

A more efficient approach would be to use an object literal and then set properties using the dot notation (`.`).

**Pros and Cons of each approach**

1. **null**:
	* Pros: Simple and straightforward.
	* Cons: Creates a new object every time, leading to unnecessary allocations.
2. **undefined**:
	* Pros: Uses a different property, making it unique compared to `null`.
	* Cons: Similar to the previous point, creates a new object.
3. **delete**:
	* Pros: Does not create a new object or allocate memory unnecessarily.
	* Cons: Requires using `delete` keyword, which can be slower.

**Other considerations**

Using `Object.create(null)` is an interesting approach. It creates a new object with no prototype chain, effectively making it a simple object without any properties. However, this approach has its own set of problems:

* It uses `Object.create`, which can be slow and may lead to performance issues.
* The resulting object does not have any properties or prototype chain.

**Alternatives**

Here are some alternative approaches that could improve performance:

1. Using an array literal and indexing into it (e.g., `[]`) instead of using objects with dot notation.
2. Using a single allocation for all properties, rather than creating a new object every time.
3. Using `let` or `const` instead of `var` to declare variables.

These alternatives would likely improve performance by reducing the number of allocations and unnecessary operations.

**Conclusion**

The benchmark is testing different approaches to setting properties in JavaScript, with varying degrees of success. While some approaches may seem simple and straightforward, they have underlying issues that can impact performance. By using more efficient techniques, such as object literals, dot notation, or array literals, we can reduce the overhead of creating new objects and improve overall performance.

As a software engineer, it's essential to understand these nuances and consider alternatives when writing JavaScript code, especially in high-performance contexts like benchmarks or production environments.

Related benchmarks:

delete vs null vs undefined vs void 0 vs Object.create(null) propertie (version: 0)

delete vs null vs undefined vs void 0 vs Object.create(null)

Comparing performance of: null vs undefined vs delete

Created: 4 years ago by: Guest

Jump to the latest result

null

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):