Benchmark: Delete vs destructure for objects without mutating

Script Preparation code:

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

Tests:

delete - assign
const copy = Object.assign({}, obj); 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: 2 days ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/136.0.0.0 Safari/537.36

Browser/OS: Chrome 136 on Linux

View result in a separate tab

Test name	Executions per second
delete - assign	3412645.5 Ops/sec
Rest object	3154661.2 Ops/sec
delete - spread operator	4113835.2 Ops/sec
delete - JSON.stringify	2729803.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

LLMs can make mistakes. Check important info.

Let's dive into explaining the provided benchmark.

**Benchmark Overview**

The benchmark, titled "Delete vs destructure for objects without mutating," compares the performance of different approaches to delete properties from an object without modifying the original object. The test cases are designed to measure the execution speed of each approach.

**Options Compared**

There are four options compared in this benchmark:

1. **delete obj.a**: This approach uses the `delete` operator to remove the property `a` from the object `obj`.
2. **const { a, ...rest } = obj;**: This approach uses destructuring assignment to extract the value of `a` from the object `obj` and assign it to a new variable `a`, while also creating a new object `rest` that includes all properties except `a`. The original object `obj` remains unchanged.
3. **const copy = { ...obj }; delete obj.a;**: This approach uses the spread operator to create a shallow copy of the object `obj`, and then deletes the property `a` from the copied object.
4. **const copy = JSON.parse(JSON.stringify(obj)); delete obj.a;**: This approach uses `JSON.stringify()` to serialize the object `obj` to a string, creates a new object `copy` by parsing the serialized string back to an object, and then deletes the property `a` from the copied object.

**Pros and Cons of Each Approach**

1. **delete obj.a**:
	* Pros: Simple and straightforward.
	* Cons: Can be slower than other approaches because it modifies the original object's internal data structure (the hash table).
2. **const { a, ...rest } = obj;**:
	* Pros: Efficient and doesn't modify the original object. Creates a new object with only the desired properties.
	* Cons: Requires using destructuring assignment, which can be less familiar to some developers.
3. **const copy = { ...obj }; delete obj.a;**:
	* Pros: Creates a shallow copy of the object, and then deletes the property, avoiding modifying the original object's internal data structure.
	* Cons: Can still be slower than other approaches because it creates an additional copy of the object.
4. **const copy = JSON.parse(JSON.stringify(obj)); delete obj.a;**:
	* Pros: Creates a deep copy of the object by serializing and deserializing it, which can be useful for complex objects with nested properties.
	* Cons: Can be slower than other approaches because it creates an additional copy of the object. Also requires using `JSON.stringify()` and `JSON.parse()`, which can be expensive operations.

**Library Used**

In this benchmark, no external libraries are used explicitly, but `JSON` is used implicitly for serializing and deserializing objects.

**Special JS Features or Syntax**

The following special JavaScript features or syntax are used in the benchmark:

* **Destructuring assignment**: Used in option 2 to extract properties from an object.
* **Spread operator**: Used in option 3 to create a shallow copy of an object.
* **JSON.stringify() and JSON.parse()**: Used in options 4 to serialize and deserialize objects, respectively.

**Other Considerations**

The benchmark is designed to measure the performance of each approach on different browsers and devices. The results can help developers understand which approach is most efficient for their use case.

Other alternatives that could be explored include:

* Using a library like Lodash's `omit()` function or the `deleteProperty()` method from some JavaScript engines.
* Comparing the performance of these approaches with other ways to remove properties, such as using the `Object.keys()` and `splice()` methods.

Related benchmarks:

Delete vs destructure for objects without mutating (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: 4 years ago by: Registered User

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 6 months ago):