Benchmark: React variable vs function for render

HTML Preparation code:

<script src="https://unpkg.com/react@16/umd/react.production.min.js"></script>
<script src="https://unpkg.com/react-dom@16/umd/react-dom.production.min.js"></script>
<script src="http://fb.me/JSXTransformer-0.12.2.js"></script>

<div id="root"></div>

<script type="text/jsx">  
class AppComp extends React.Component {
  constructor() {
    super();
    this.state = {
      count : 0,
      type : 'fn'
    }
  }
  render() {
    return (
      <div>
        {this.state.type === 'fn' ?
          <DisplayAsFn  value={this.state.count} />
        :
          <DisplayAsVar value={this.state.count} />
        }
      </div>
    );
  }
}
function DisplayAsFn({value}) {
  const renderValue = () => {
    return <span>{value}</span>
  };
  return <div>Fn : {renderValue()}</div>
}
function DisplayAsVar({value}) {
  const renderValue = <span>{value}</span>
  return <div>Var : {renderValue}</div>
}
var appComp = ReactDOM.render(
  <AppComp />,
  document.querySelector('#root')
);
function add1() {
  appComp.setState({count: appComp.state.count + 1});
}
function setType(type) {
  appComp.setState({type});
}
</script>

Tests:

Render with Fn
appComp.setState({ count: appComp.state.count + 1, type : 'fn' });
Render with Var
appComp.setState({ count: appComp.state.count + 1, type : 'var' });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Render with Fn
Render with Var

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what is being tested.

**Benchmark Overview**

The benchmark compares the performance of two approaches to rendering rules in a React application:

1. **Variables**: Defining variables to hold render rules, as shown in the `DisplayAsVar` function.
2. **Anonymous Functions (Fn)**: Creating anonymous functions to hold render rules, as shown in the `DisplayAsFn` function.

**Options Compared**

The benchmark is testing two options:

* Using a variable (`var`) to store the render rule.
* Using an anonymous function (`fn`) to store the render rule.

**Pros and Cons of Each Approach**

1. **Variables (Var)**:
	* Pros:
		+ Easier to understand and debug, as the code is more straightforward.
		+ Can be used in a wider range of contexts, including non-JavaScript environments.
	* Cons:
		+ May lead to slower performance due to the overhead of variable lookups.
2. **Anonymous Functions (Fn)**:
	* Pros:
		+ Can provide faster performance, as the anonymous function can be optimized by the JavaScript engine.
		+ Allows for more flexibility in handling different render rules.
	* Cons:
		+ May be harder to understand and debug, especially for developers not familiar with closures.

**Library: JSXTransformer**

The benchmark uses the `JSXTransformer` library to enable JSX syntax support. JSX is a syntax extension that allows developers to write HTML-like code in their JavaScript files. The `JSXTransformer` library is responsible for transforming this syntax into standard JavaScript code that can be executed by the browser.

**Special JS Feature: Closures**

The benchmark uses anonymous functions (closures) to store and apply render rules. A closure is a function that has access to its own scope, including variables from its outer function. In this case, the `DisplayAsFn` and `DisplayAsVar` functions create closures over the `value` parameter, which allows them to modify the render rule based on the value of `state.count`.

**Other Alternatives**

If you're interested in exploring other alternatives for rendering rules or optimizing performance in React applications, here are a few options:

* **Use `React.createRef()`**: Instead of defining variables or anonymous functions to store render rules, consider using `React.createRef()` to create references that can be used to update the DOM.
* **Implement a custom render function**: If you need more control over the rendering process, consider implementing a custom render function using React's `render` method.
* **Use a library like react-immutable**: Immutable.js is a library that provides immutable data structures and functions for optimizing performance in React applications.

I hope this explanation helps! Let me know if you have any further questions.

Related benchmarks:

React variable vs function for render (version: 0)

I have a question about the performance of generating anon-functions many times instead of simply defining variables to hold render rules.

Comparing performance of: Render with Fn vs Render with Var

Created: 6 years ago by: Registered User

Jump to the latest result

Render with Fn

Render with Var

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):