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

Test name	Executions per second
object literal	730089856.0 Ops/sec
adding properties	21080048.0 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.

Related benchmarks:

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

Comparing performance of: object literal vs adding properties

Created: 2 years ago by: Registered User

Jump 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):