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>

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

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Experimental features:

Memory measurements supported only in Chrome.
For precise memory measurements Chrome must be launched with --enable-precise-memory-info flag.
More information: Monitoring JavaScript Memory

Test case name	Result
Render with Fn
Render with Var

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/117.0.0.0 Safari/537.36

Browser/OS: Chrome 117 on Windows

View result in a separate tab

Test name	Executions per second
Render with Fn	339941.1 Ops/sec
Render with Var	342274.9 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

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:

Variables: Defining variables to hold render rules, as shown in the DisplayAsVar function.
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

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.
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.

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: 5 years ago by: Registered User

Jump to the latest result

Render with Fn

Render with Var

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):