Benchmark: object assign vs mutation

Tests:

Object assign
const resumeToken = "abc123" const options = { TableName: 'undefined', IndexName: 'ActiveIndex', KeyConditionExpression: 'active = :active', FilterExpression: 'autoCancelProcessingDate <= :toDate' } const newOptions = Object.assign({}, {...options, ExclusiveStartKey: resumeToken});
Object mutation
const resumeToken = "abc123" const options = { TableName: 'undefined', IndexName: 'ActiveIndex', KeyConditionExpression: 'active = :active', FilterExpression: 'autoCancelProcessingDate <= :toDate' } options.ExclusiveStartKey = resumeToken;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object assign
Object mutation

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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I'll break down the provided benchmark and explain what's being tested, compared, and their pros and cons.

**Benchmark Overview**

The benchmark compares two approaches to create an object with similar properties: using `Object.assign()` (also known as "object assign" in the benchmark) versus directly modifying the original object by assigning new values to its properties (referred to as "mutation" in the benchmark).

**Options Compared**

1. **Object Assign**: This approach creates a new object and assigns the existing object's properties to it using `Object.assign()`. The resulting object is created by copying the source object's enumerable properties.
2. **Mutation**: This approach directly modifies the original object by assigning new values to its properties.

**Pros and Cons**

* **Object Assign**
	+ Pros:
		- Creates a new object, which can help prevent unexpected side effects when modifying existing objects.
		- Can be safer in certain situations where mutable state is not desired (e.g., in functional programming).
	+ Cons:
		- Creates an unnecessary copy of the object's properties, which can lead to increased memory usage and slower performance for large objects.
* **Mutation**
	+ Pros:
		- Modifies the original object directly, which can be more efficient than creating a new object.
	+ Cons:
		- Can lead to unexpected side effects if not done carefully, as modifications can affect other parts of the code.

**Library and Special JS Feature**

There are no libraries used in this benchmark. However, it's worth noting that `Object.assign()` is a built-in JavaScript method, so there's no additional library required for its use.

No special JavaScript features or syntax are being tested in this benchmark.

**Alternative Approaches**

Other approaches to create an object with similar properties include:

1. **Spread Operator (`...`)**: This approach uses the spread operator to create a new object and assigns the existing object's properties to it.
2. **Constructors**: You can use constructors (e.g., `Object.create()`) to create a new object and assign properties to it.

While these alternatives are not being tested in this benchmark, they can be useful in different situations:

* Spread Operator: Creates an object with the same properties as the original object, but without modifying the original.
* Constructors: Provides more control over object creation and assignment of properties.

Keep in mind that the choice of approach depends on the specific use case and requirements of your application.

Related benchmarks:

object assign vs mutation (version: 0)

Comparing performance of: Object assign vs Object mutation

Created: 3 years ago by: Guest

Jump to the latest result

Object assign

Object mutation

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):