Benchmark: defineProperty descriptor configurable

Script Preparation code:

var base = { value: 'data' };

var object = { ...base, get prop() { return this.value; }, getProp() { return this.value; } };

var configurable = Object.defineProperty({ ...base }, 'prop', {
  get() { return this.value; },
  configurable: true,
});

var unconfigurable = Object.defineProperty({ ...base }, 'prop', {
  get() { return this.value; },
  configurable: false,
});

var out = { value: '' };

Tests:

direct access
out.value = base.value;
direct fn return
out.value = object.getProp();
configurable getter
out.value = configurable.prop;
unconfigurable getter
out.value = unconfigurable.prop;
direct getter
out.value = object.prop;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
direct access
direct fn return
configurable getter
unconfigurable getter
direct getter

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.0.0 Safari/537.36

Browser/OS: Chrome 128 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
direct access	16059963.0 Ops/sec
direct fn return	16056291.0 Ops/sec
configurable getter	16096501.0 Ops/sec
unconfigurable getter	15857382.0 Ops/sec
direct getter	16094200.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark and explain what's being tested.

**Benchmark Definition**

The benchmark defines two objects, `base` and `object`, which contain a shared property `value`. The property is initially set to `'data'`.

The benchmark then creates two descriptors:

1. A configurable descriptor (`configurable`) for the `prop` property of `base`, with a getter function that returns `this.value`.
2. An unconfigurable descriptor (`unconfigurable`) for the `prop` property of `base`, with the same getter function.

Additionally, two separate objects, `out1` and `out2`, are created to store the results of accessing the `prop` property.

**Test Cases**

There are five test cases:

1. **Direct Access**: Assigns the value of `base.value` directly to `out1.value`.
2. **Direct Function Return**: Assigns the result of calling `object.getProp()` (which is a getter function) to `out2.value`.
3. **Configurable Getter**: Assigns the result of calling `configurable.prop` to `out1.value`. This test case verifies that the configurable getter works correctly.
4. **Unconfigurable Getter**: Assigns the result of calling `unconfigurable.prop` to `out2.value`. This test case verifies that the unconfigurable getter does not work correctly (as expected).
5. **Direct Getter**: Assigns the result of calling `object.prop` directly to `out1.value`.

**Pros and Cons**

* **Configurable Getter**: This approach allows for more flexibility in setting up getters, as the descriptor can be customized. However, it may lead to performance overhead due to the dynamic creation of descriptors.
* **Unconfigurable Getter**: This approach provides a clear and predictable behavior, but it makes it difficult to customize or modify the getter function without changing the underlying object structure.

**Libraries and Features**

* `Object.defineProperty()`: A JavaScript method used to define properties on objects. It takes three arguments: the object, the property name, and an options object with descriptor properties.
* **Getter Functions**: The `get()` property of a descriptor is a getter function that is called when the property is accessed.

**Special JS Features**

None mentioned in this explanation.

**Alternatives**

Other alternatives for creating getters or descriptors include:

* Using arrow functions or regular functions as getter functions
* Using the `Object.create()` method to create an object with a custom prototype and define properties on it
* Using a library like Lodash or Underscore.js, which provides utility functions for working with objects and arrays.

However, these alternatives may not provide the same level of control and customization as using `Object.defineProperty()`.

Related benchmarks:

defineProperty descriptor configurable (version: 0)

Comparing performance of: direct access vs direct fn return vs configurable getter vs unconfigurable getter vs direct getter

Created: one year ago by: Guest

Jump to the latest result

direct access

direct fn return

configurable getter

unconfigurable getter

direct getter

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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