Benchmark: cost of adding new properties to object after creation.

Script Preparation code:

function objLiteral() {
  
	const obj = {
      _chanPutMsg_m: undefined,
      _doneVal_m: 3213,
      _name: true,
      _args: false,
      _state: "RUNNING",
      _doneCh: undefined,
      _childS: undefined,
      _sleepTimeout_m: undefined,
      _onCancel_m: undefined,
      _cancelCh: undefined,
  	} 
    
    return obj
}

function addProps() {
  
  const obj2 = {}
  
  obj2._chanPutMsg_m = undefined
  obj2._doneVal_m = 3213
  obj2._name = true
  obj2._args = false
  obj2._state = "RUNNING"
  obj2._doneCh = undefined
  obj2._childS = undefined
  obj2._sleepTimeout_m = undefined
  obj2._onCancel_m = undefined
  obj2._cancelCh = undefined
  
  return obj2
}

Tests:

object literal
objLiteral()
adding properties
addProps()

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
object literal
adding properties

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:138.0) Gecko/20100101 Firefox/138.0

Browser/OS: Firefox 138 on Windows

View result in a separate tab

object literal

730.1M/s

adding properties

21.1M/s

View exact numbers

Test name	Executions per second
✓ object literal	730,089,856 Ops/sec
adding properties	21,080,048 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark definition and test cases to understand what is being tested.

**Benchmark Definition**

The provided JSON represents two JavaScript microbenchmarks:

1. **`objLiteral()`**: This function creates an object literal using the `const obj = { ... }` syntax. The objective of this benchmark is to measure the cost of creating a new object using an object literal.
2. **`addProps()`**: This function creates a new object by assigning properties to it, similar to how you would create an object literal. However, instead of directly creating the object, `addProps()` first creates an empty object (`const obj2 = {}`) and then assigns the properties.

**Options Compared**

Two approaches are being compared:

1. **Object Literal (`objLiteral()`)**: This approach creates a new object using the `const obj = { ... }` syntax.
2. **Property Assignment (`addProps()`)**: This approach first creates an empty object (`const obj2 = {}`) and then assigns properties to it.

**Pros and Cons of Each Approach**

1. **Object Literal (`objLiteral()`)**
	* Pros:
		+ More concise and readable syntax.
		+ Can be faster because the object is created in a single statement.
	* Cons:
		+ May incur additional overhead due to the need for type checking and syntax parsing.
2. **Property Assignment (`addProps()`)**
	* Pros:
		+ Can be more efficient because it avoids the need for type checking and syntax parsing.
	* Cons:
		+ Requires an extra step of creating an empty object before assigning properties.

**Library Usage**

None of the provided benchmarks use a library that affects the outcome of the benchmark.

**Special JavaScript Features or Syntax**

There is no special JavaScript feature or syntax being used in these benchmarks. The focus is on comparing two simple approaches to create objects.

**Other Alternatives**

If you wanted to add more complexity to this benchmark, here are some alternative approaches:

* Using a class constructor instead of object literals.
* Creating an object using the `Object.create()` method with a prototype.
* Using a library like Lodash's `_.assign()` function to assign properties.

Keep in mind that these alternatives may introduce additional variables and complexities that could affect the benchmark results.

cost of adding new properties to object after creation. (version: 0) Benchmark.js

Comparing performance of: `object literal vs adding properties`

Created: 3 years ago by: Registered User

Go to the latest result

object literal

adding properties

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

cost of adding new properties to object after creation. (version: 0) Benchmark.js

Comparing performance of: object literal vs adding properties

Created: 3 years ago by: Registered User

Go to the latest result

object literal

adding properties

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Related benchmarks

Comparing performance of: `object literal vs adding properties`