Benchmark: Delete vs destructure for objects without mutating s

Script Preparation code:

var obj = {
  a:1,
  b:2,
  c:3
}

Tests:

delete - assign
delete obj.a
Rest object
const { a, ...rest } = obj;
delete - spread operator
const copy = { ...obj } delete obj.a
delete - JSON.stringify
const copy = JSON.parse(JSON.stringify(obj)); delete obj.a

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
delete - assign
Rest object
delete - spread operator
delete - JSON.stringify

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 9 months ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:124.0) Gecko/20100101 Firefox/124.0

Browser/OS: Firefox 124 on Linux

View result in a separate tab

Test name	Executions per second
delete - assign	96355000.0 Ops/sec
Rest object	24242210.0 Ops/sec
delete - spread operator	21174394.0 Ops/sec
delete - JSON.stringify	3591427.8 Ops/sec

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

LLMs can make mistakes. Check important info.

**Benchmark Overview**

MeasureThat.net is a website that allows users to create and run JavaScript microbenchmarks. The provided benchmark measures the performance of deleting properties from an object without mutating the original object.

**Script Preparation Code**

The script preparation code for this benchmark is:
```javascript
var obj = {
  a:1,
  b:2,
  c:3
};
```
This creates a simple object with three properties: `a`, `b`, and `c`.

**Individual Test Cases**

There are four test cases, each measuring the performance of deleting properties from the object using different approaches:

1. **delete obj.a**: This approach uses the `delete` keyword to delete the property `a` from the object.
2. **const { a, ...rest } = obj;**: This approach uses destructuring to extract the value of `a` from the object and creates a new object with the remaining properties (`b` and `c`) assigned to the variable `rest`.
3. **const copy = { ...obj }; delete obj.a;**: This approach creates a shallow copy of the object using the spread operator (`{ ...obj }`) and then deletes the property `a` from the copied object.
4. **const copy = JSON.parse(JSON.stringify(obj)); delete obj.a**: This approach creates a deep copy of the object using `JSON.parse(JSON.stringify(obj))` and then deletes the property `a` from the copied object.

**Library and Special JS Features**

None of these test cases rely on any external libraries or special JavaScript features. The only library used is JavaScript itself, which is implicitly provided by MeasureThat.net's environment.

**Comparison of Approaches**

The four approaches have different performance characteristics:

1. **delete obj.a**: This approach directly deletes the property from the original object, making it a fast and efficient way to remove properties.
2. **const { a, ...rest } = obj;**: This approach creates a new object with the remaining properties, which can be slower than deleting the property directly since it involves creating an intermediate object.
3. **const copy = { ...obj }; delete obj.a;**: This approach creates a shallow copy of the original object and then deletes the property from the copied object. This approach is similar to the first one but introduces additional overhead due to the creation of an intermediate object.
4. **const copy = JSON.parse(JSON.stringify(obj)); delete obj.a**: This approach creates a deep copy of the original object using `JSON.parse(JSON.stringify(obj))`, which can be slower than the other approaches since it involves serializing and deserializing the object.

**Pros and Cons**

Here are some pros and cons for each approach:

1. **delete obj.a**:
	* Pros: Fast and efficient way to delete properties.
	* Cons: May modify the original object if used with an uninitialized variable or in a context where side effects are expected.
2. **const { a, ...rest } = obj;**:
	* Pros: Creates a new object with remaining properties, which can be useful for creating immutable data structures.
	* Cons: Can be slower than deleting the property directly since it involves creating an intermediate object.
3. **const copy = { ...obj }; delete obj.a;**:
	* Pros: Similar to `delete obj.a` but creates a shallow copy of the original object first.
	* Cons: Introduces additional overhead due to the creation of an intermediate object.
4. **const copy = JSON.parse(JSON.stringify(obj)); delete obj.a**:
	* Pros: Creates a deep copy of the original object, which can be useful for preserving data structures with complex relationships.
	* Cons: Can be slower than other approaches since it involves serializing and deserializing the object.

**Alternatives**

Other alternatives to these approaches include:

1. **for...in loop**: Instead of using `delete`, you could use a `for...in` loop to iterate over the object's properties and delete each one individually.
2. **Object.keys() and splice()**: You could use `Object.keys()` to get an array of the object's property names and then use `splice()` to remove each property from the array.
3. **Using a library or framework**: Depending on your specific use case, you may be able to leverage libraries or frameworks that provide optimized methods for deleting properties, such as Lodash's `pick()` function.

These alternatives have different trade-offs in terms of performance, readability, and maintainability, so it's essential to choose the approach that best fits your specific requirements.

Related benchmarks:

Delete vs destructure for objects without mutating s (version: 0)

Measure the performance of delete versus removing a prop from an object without mutating

Comparing performance of: delete - assign vs Rest object vs delete - spread operator vs delete - JSON.stringify

Created: 9 months ago by: Guest

Jump to the latest result

delete - assign

Rest object

delete - spread operator

delete - JSON.stringify

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):