Benchmark: class scope access - cache vs this

Tests:

this
class k { constructor() { this.x = 1, this.y = 1, this.z = 1, this.a = 1, this.b = 1, this.c = 1; } } let r = new k();
cached this
class k { constructor() { let m = this; m.x = 1, m.y = 1, m.z = 1, m.a = 1, m.b = 1, m.c = 1; } } let r = new k();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
this
cached this

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the benchmark and explore what's being tested.

**Benchmark Overview**

The benchmark, hosted on MeasureThat.net, is designed to compare two approaches for accessing a class variable in JavaScript: `this` and caching `this`. The goal is to determine which approach is faster and more efficient.

**Test Cases**

There are two test cases:

1. **"this"`**: This test case defines a class `k` with a constructor that assigns six variables (`x`, `y`, `z`, `a`, `b`, and `c`) to the value 1 using the `this` keyword.
2. **"cached this"`**: This test case defines the same class `k`, but in the constructor, it creates a reference to `this` (denoted as `m`) and assigns the variables using `m`. The intention is to cache the `this` reference.

**Options Compared**

In this benchmark, we have two options being compared:

* **Direct Access (`this`)**: Assigns variables directly to `this`, which means the variable's scope is determined at runtime.
* **Caching `this`**: Creates a cached reference to `this` using a variable (in this case, `m`). This approach aims to avoid the overhead of accessing `this` multiple times.

**Pros and Cons**

Here are some pros and cons for each approach:

* **Direct Access (`this`)**:
	+ Pros: Simple, intuitive syntax.
	+ Cons: May incur additional runtime overhead due to scope resolution.
* **Caching `this`**:
	+ Pros: Can potentially reduce runtime overhead by avoiding scope resolution.
	+ Cons: Requires creating an extra variable (`m`) to cache the reference.

**Library and Purpose**

In both test cases, no libraries are used. The benchmark focuses solely on the JavaScript engine's performance optimizations for class variable access.

**Special JS Feature or Syntax**

There is no special JavaScript feature or syntax being tested in this benchmark. The code only uses standard JavaScript constructs.

**Other Alternatives**

While MeasureThat.net provides a specific benchmarking framework, other alternatives exist:

* **Benchmarking libraries**: Libraries like Benchmark.js or jsperf can be used to create and run benchmarks.
* **JavaScript testing frameworks**: Frameworks like Jest or Mocha provide built-in support for running tests and benchmarks.

By using these alternatives, you can create your own benchmarks to compare different JavaScript code snippets or explore performance optimizations.

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:99.0) Gecko/20100101 Firefox/99.0

Browser/OS: Firefox 99 on Mac OS X 10.15

View result in a separate tab

Test name	Executions per second
this	289834.2 Ops/sec
cached this	285824.5 Ops/sec

Related benchmarks:

class scope access - cache vs this (version: 0)

Comparing performance of: this vs cached this

Created: 2 years ago by: Guest

Jump to the latest result

this

cached this

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):