Benchmark: Object.getOwnPropertyDescriptor().value vs Reflect.get() vs object[]

Tests:

Object.getOwnPropertyDescriptor()
let object1 = { property1: 42 }; Object.getOwnPropertyDescriptor(object1, 'property1').value; Object.getOwnPropertyDescriptor(object1, 'noSuchProperty')?.value;
Reflect.get()
let object1 = { property1: 42 }; Reflect.get(object1, 'property1'); Reflect.get(object1, 'noSuchProperty');
object[]
let object1 = { property1: 42 }; object1["property1"] object1["noSuchProperty"]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.getOwnPropertyDescriptor()
Reflect.get()
object[]

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 months ago)

User agent: Mozilla/5.0 (Android 11; Mobile; rv:136.0) Gecko/136.0 Firefox/136.0

Browser/OS: Firefox Mobile 136 on Android

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Test name	Executions per second
Object.getOwnPropertyDescriptor()	5060563.5 Ops/sec
Reflect.get()	76338728.0 Ops/sec
object[]	536081696.0 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated 3 months ago):

LLMs can make mistakes. Check important info.

The benchmark defined examines three different methods for accessing object property values in JavaScript, specifically:

1. **Object.getOwnPropertyDescriptor()**
2. **Reflect.get()**
3. **Bracket notation (object[])**

### Test Cases Overview

1. **Object.getOwnPropertyDescriptor()**:
   - This method retrieves the descriptor for a property specified by a string name, returning an object that contains all attributes (like value, writable, enumerable, and configurable) of that property.
   - The benchmark code executes the descriptor retrieval for an existing property and a non-existent property (using optional chaining to avoid errors).
   - Pros:
     - Provides comprehensive details about the property, which can be useful when introspecting object structures.
   - Cons:
     - More overhead compared to direct property access; it involves creating a descriptor object, which may lead to performance overhead, especially in tight loops or performance-critical code.

2. **Reflect.get()**:
   - Part of the Reflect API introduced in ECMAScript 2015 (ES6), this function retrieves the value of a property from a target object.
   - Similar to the previous method, it can access existing properties and also handle non-existent properties gracefully.
   - Pros:
     - Offers a more standardized approach while maintaining direct property access speeds; can be beneficial for accessing properties dynamically or in proxies.
   - Cons:
     - Still incurs some performance overhead compared to simpler access methods (bracket or dot notation).

3. **Bracket notation (object[])**:
   - This is the standard way to access properties of an object using square brackets and a string key.
   - The benchmark code checks for both an existing and a non-existent property.
   - Pros:
     - Fastest among the three methods, offering straightforward and direct property access with minimal overhead; ideal for common access patterns.
   - Cons:
     - Lacks introspective capabilities, requiring additional logic or methods if more information (like property descriptor) is needed.

### Benchmark Results

The benchmark results demonstrate the executions per second for each method across the same environment (Chrome 131 on Windows 10):

- **Bracket Notation (object[])**: 85,814,536 executions/second
- **Reflect.get()**: 19,231,816 executions/second
- **Object.getOwnPropertyDescriptor()**: 13,847,106 executions/second

From this data, we can conclude that bracket notation is the most performant approach for direct property access, significantly outperforming both Reflect.get() and Object.getOwnPropertyDescriptor().

### Other Considerations

When deciding which method to use, engineers should consider the specific scenario:

- **Use `object[]`** when performance is paramount and the structure of the object is straightforward.
- **Use `Reflect.get()`** when you require a balance between performance and the need for dynamic access within the context of proxies.
- **Use `Object.getOwnPropertyDescriptor()`** when property metadata is required for an object's properties, but be wary of its performance cost.

In summary, while bracket notation excels in performance and simplicity, Reflect.get() and Object.getOwnPropertyDescriptor() have their respective use cases, especially in contexts needing more dynamic or introspective capabilities.

Related benchmarks:

Object.getOwnPropertyDescriptor().value vs Reflect.get() vs object[] (version: 1)

Comparing performance of: Object.getOwnPropertyDescriptor() vs Reflect.get() vs object[]

Created: 3 months ago by: Guest

Jump to the latest result

Object.getOwnPropertyDescriptor()

Reflect.get()

object[]

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 3 months ago):