Benchmark: Delete vs set undefined vs in/delete

Script Preparation code:

var obj = {a:1, b:2};

Tests:

Delete
delete obj.a; delete obj.b; delete obj.c; delete obj.d;
Set undefined
obj.a = undefined; obj.b = undefined; obj.c = undefined; obj.d = undefined;
in/delete
if ("a" in obj) { delete obj.a; } if ("a" in obj) { delete obj.b; } if ("a" in obj) { delete obj.c; } if ("a" in obj) { delete obj.d; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Delete
Set undefined
in/delete

Fastest: N/A

Slowest: N/A

Latest run results:

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

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Let's break down the provided benchmark and explain what is being tested, compared options, pros and cons, and other considerations.

**Benchmark Overview**

The benchmark is designed to compare the performance of three different approaches for removing properties from an object in JavaScript:

1. `delete` keyword
2. Assigning `undefined` to a property (`obj.a = undefined;`)
3. Using the `in` operator with `delete` (`if ("a" in obj) { delete obj.a; }`)

**Test Cases**

There are three test cases, each representing one of the above approaches.

1. **Delete**: This test case uses the `delete` keyword to remove properties from the object.
```javascript
delete obj.a;
delete obj.b;
delete obj.c;
delete obj.d;
```
2. **Set undefined**: This test case assigns `undefined` to a property to effectively remove it from the object.
```javascript
obj.a = undefined;
obj.b = undefined;
obj.c = undefined;
obj.d = undefined;
```
3. **in/delete**: This test case uses the `in` operator to check if a property exists in the object, and then uses the `delete` keyword to remove it.
```javascript
if ("a" in obj) { delete obj.a; }
if ("b" in obj) { delete obj.b; }
if ("c" in obj) { delete obj.c; }
if ("d" in obj) { delete obj.d; }
```
**Options Compared**

The benchmark compares the performance of these three approaches:

* `delete` keyword
* Assigning `undefined` to a property (`obj.a = undefined;`)
* Using the `in` operator with `delete` (`if ("a" in obj) { delete obj.a; }`)

**Pros and Cons**

Here are some pros and cons of each approach:

1. **Delete**:
	* Pros: Simple and straightforward.
	* Cons: May not be supported in older browsers or environments that don't support `delete`.
2. **Set undefined**:
	* Pros: Wide browser support, works even if the property doesn't exist.
	* Cons: May cause unexpected behavior in certain situations (e.g., when using `hasOwnProperty()`).
3. **in/delete**:
	* Pros: Works well for properties that don't exist, but can be slower than `delete` keyword due to the additional check.
	* Cons: Additional check can introduce overhead.

**Library and Special JS Features**

There is no library used in this benchmark, but it's worth noting that some JavaScript engines (like V8) have optimizations for the `in` operator that might affect performance.

No special JS features are mentioned in this benchmark.

**Alternatives**

Other alternatives to removing properties from an object include:

* Using a library like Lodash or Ramda, which provide utility functions for working with objects.
* Using a different data structure, such as an array or a Map, if possible.
* Using a more modern JavaScript feature, like `Object.remove()` (not supported in older browsers).

Keep in mind that the choice of approach depends on the specific use case and requirements. The benchmark is designed to provide a general comparison of these approaches and help users understand their performance characteristics.

Related benchmarks:

Delete vs set undefined vs in/delete (version: 0)

Comparing performance of: Delete vs Set undefined vs in/delete

Created: 3 years ago by: Guest

Jump to the latest result

Delete

Set undefined

in/delete

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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