Benchmark: Member access vs ArrayBuffer backed data

Script Preparation code:

buf = new ArrayBuffer(4);
dv = new DataView(buf);

obj = { x: 0 };

definedObj = new Object();
Object.defineProperty(definedObj, "x", { value: 0, writable: true });

accessorObj = new Object();
Object.defineProperty(accessorObj, "x", {
  get() {
    return dv.getInt32(0, true);
  },
  set(val) {
  	dv.setInt32(0, val, true);
  }
});

Tests:

Object read
obj.x
Object write
obj.x = 5;
Defined object read
definedObj.x
Defined object write
definedObj.x = 5;
accessorObj read
accessorObj.x
accessorObj write
accessorObj.x = 5;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object read
Object write
Defined object read
Defined object write
accessorObj read
accessorObj write

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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

LLMs can make mistakes. Check important info.

Measuring performance of JavaScript code is essential for optimizing and improving the overall efficiency of web applications.

The provided benchmark, `Member access vs ArrayBuffer backed data`, tests the performance difference between accessing object properties using dot notation (`obj.x`) versus using an accessor object with getter and setter functions (`accessorObj.x`).

Here's a breakdown of what each test case measures:

1. **Object read**: Measuring the time taken to access the `x` property of the `obj` object directly.
2. **Object write**: Measuring the time taken to assign a value to the `x` property of the `obj` object directly.
3. **Defined object read**: Measuring the time taken to access the `x` property of the `definedObj` object, which has been defined using `Object.defineProperty()`.
4. **Defined object write**: Measuring the time taken to assign a value to the `x` property of the `definedObj` object.
5. **Accessor Object read**: Measuring the time taken to access the `x` property of the `accessorObj` object, which is an accessor object with getter and setter functions.
6. **Accessor Object write**: Measuring the time taken to assign a value to the `x` property of the `accessorObj` object.

Now, let's discuss the pros and cons of each approach:

**Dot notation (obj.x)**

Pros:

* Easy to read and maintain
* No additional overhead for creating accessor objects or defining getters and setters

Cons:

* Can lead to slower performance due to the need to traverse the object property chain
* May result in more complex code when working with nested objects

**Accessor Object**

Pros:

* Can provide better performance by avoiding the need to traverse the object property chain
* Allows for fine-grained control over read and write access, which can be beneficial in certain scenarios

Cons:

* Requires additional overhead for creating accessor objects and defining getters and setters
* Can make code more complex and harder to read

In this benchmark, the tests suggest that using an accessor object with getter and setter functions (`accessorObj.x`) can provide a significant performance boost compared to accessing object properties directly using dot notation (`obj.x`). This is likely due to the reduced overhead of traversing the object property chain.

Other considerations:

* The use of `ArrayBuffer` backed data in the benchmark preparation code may also have an impact on performance, as it allows for more efficient memory allocation and deallocation.
* The specific version of Chrome 116 being tested (116.0.0.0) may also introduce some differences in behavior or performance compared to other versions.

Alternatives:

* For measuring object property access performance, other benchmarks like `Benchmark.js` or `jsperf` could be used.
* For testing accessor objects and getters/setters, custom benchmarking scripts or libraries like `fast-assert` or `jest-benchmark` might be more suitable.

Related benchmarks:

Member access vs ArrayBuffer backed data (version: 0)

Comparing performance of: Object read vs Object write vs Defined object read vs Defined object write vs accessorObj read vs accessorObj write

Created: 2 years ago by: Guest

Jump to the latest result

Object read

Object write

Defined object read

Defined object write

accessorObj read

accessorObj write

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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