Benchmark: object property initialize vs add dynamically

Tests:

add properties dynamically
const user = {}; user.name = 'John'; user.age = 30;
initialize with object literal
const user = { name: 'John', age: 30 };

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
add properties dynamically
initialize with object literal

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

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Test name	Executions per second
add properties dynamically	100521152.0 Ops/sec
initialize with object literal	684161344.0 Ops/sec

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

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I'd be happy to help explain the benchmark.

**Benchmark Overview**

The benchmark is designed to test two approaches to initializing object properties in JavaScript: using an object literal and adding properties dynamically.

**Options Compared**

Two options are compared:

1. **Initialization with Object Literal**: This approach uses an object literal (e.g., `{ name: 'John', age: 30 }`) to initialize the object.
2. **Adding Properties Dynamically**: This approach adds properties to an existing object using assignment statements (e.g., `const user = {}; user.name = 'John'; user.age = 30;`).

**Pros and Cons of Each Approach**

1. **Initialization with Object Literal**:
	* Pros:
		+ More concise and readable code
		+ Can lead to better performance due to reduced overhead of dynamic property assignment
	* Cons:
		+ Limited flexibility if initial properties need to be computed or retrieved from external data sources
2. **Adding Properties Dynamically**:
	* Pros:
		+ Highly flexible, as new properties can be added at runtime without changing the original code structure
	* Cons:
		+ Can lead to performance overhead due to dynamic property assignment and potential cache misses

**Library and Special Features**

There is no specific library mentioned in the benchmark definition. However, the tests do use JavaScript features such as const declarations and template literals (e.g., `{ name: 'John', age: 30 }`).

**Other Considerations**

1. **Object Creation**: Both approaches create an object with the same properties. The difference lies in how those properties are initialized.
2. **Property Access**: In both cases, property access is performed using dot notation (e.g., `user.name`).
3. **Cache Misses**: Adding properties dynamically can lead to cache misses due to the overhead of resolving the new property name.

**Alternative Approaches**

Other approaches to initializing object properties include:

1. **Using a Factory Function**: Create an object factory function that returns an object with initial properties.
2. **Using an Object Constructor**: Define an object constructor (e.g., `function User() { this.name = 'John'; this.age = 30; }`) and instantiate it to create an object with initial properties.
3. **Using a Library or Framework**: Utilize a library or framework that provides built-in support for initializing objects with default values or properties.

These alternative approaches may offer different trade-offs in terms of conciseness, flexibility, performance, or maintainability, depending on the specific use case and requirements.

Related benchmarks:

object property initialize vs add dynamically (version: 0)

v8 engine optimization check

Comparing performance of: add properties dynamically vs initialize with object literal

Created: 2 years ago by: Guest

Jump to the latest result

add properties dynamically

initialize with object literal

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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