开源日报每天推荐一个 GitHub 优质开源项目和一篇精选英文科技或编程文章原文，坚持阅读《开源日报》，保持每日学习的好习惯。

2024年1月28日，开源日报第1088期：
今日推荐开源项目：《drawio-desktop》
今日推荐英文原文：《A Super Simple Guide to the Render Props Pattern in React》

开源项目

今日推荐开源项目：《drawio-desktop》传送门：项目链接

推荐理由： drawio-desktop是一个基于Electron的图表和白板桌面应用程序，它包装了核心的draw.io编辑器

网站直达：www.diagrams.net

英文原文

今日推荐英文原文：A Super Simple Guide to the Render Props Pattern in React

推荐理由：渲染属性模式是React中一种优雅的模式，用于在组件间以清晰可重用的方式共享数据或功能，创建渲染属性组件如DateProvider，通过渲染传递的函数提供数据，提高复用性

A Super Simple Guide to the Render Props Pattern in React

Render Props Pattern in React

Hey there, React enthusiasts! Today, we’re diving into an elegant and versatile pattern in React: the Render Props pattern. This pattern allows you to share data or functionality between components in a clean and reusable way, and it’s simpler than you might think.

What’s the Render Props Pattern?

Imagine you’re sharing your favorite book with a friend. You don’t just give them the book; you read it together, enjoying each page. The Render Props pattern is like that shared reading experience. It’s a way to share data or functionality by rendering a function as a child component. This function receives data as an argument and returns what to render based on that data.

When Do We Use the Render Props Pattern in React?

The Render Props pattern is handy when you want to share data or functionality between components, especially in situations where you need to customize the rendering based on that data. It’s a versatile approach for making your React components more reusable.

Creating a Render Props Component

Let’s create a simple Render Props component that shares the current date:

import React from 'react';

class DateProvider extends React.Component {
  render() {
    const currentDate = new Date();
    return this.props.children(currentDate);
  }
}

export default DateProvider;

In this example, DateProvider is our Render Props component. It provides the current date by rendering the function passed as children and passing the currentDate as an argument.

Using the Render Props Component

Now, let’s see how we can use the DateProvider to display the current date in our app:

import React from 'react';
import DateProvider from './DateProvider';

class App extends React.Component {
  render() {
    return (
      <div className="App">
        <h1>Welcome to My React App</h1>
        <DateProvider>
          {(currentDate) => (
            <p>Today's date is: {currentDate.toDateString()}</p>
          )}
        </DateProvider>
      </div>
    );
  }
}

export default App;

In this example:

We import the DateProvider component.
Inside the App component, we wrap the content we want to share the current date with inside the <DateProvider> component.
We render a function as a child, which receives the currentDate as an argument and returns what to render. In this case, we display the current date.

Real-World Example: Token Validation

Now, let’s take the Render Props pattern to the real world. Imagine you have a React app that requires user authentication. You want to validate user data stored localStorage against an API. If successful, you'd like to pass the user's ID to child components or display an error message if the validation fails.

Here’s how you can modify your AzureProvider component to use the Render Props pattern:

import React, { useEffect, useState } from 'react';

const AzureProvider = (props) => {
  const [error, setError] = useState(null);
  const [globalProvider, setGlobalProvider] = useState(null);

  const validate = async () => {
    let provider;
    try {
      const token = localStorage.getItem('userToken');

      if (!token) {
        throw new Error('No user token found in localStorage');
      }

      // Make an API call to validate the token
      const response = await fetch('https://your-api-endpoint.com/validate', {
        method: 'POST',
        headers: {
          'Authorization': `Bearer ${token}`,
        },
      });

      if (!response.ok) {
        throw new Error('Token validation failed');
      }

      // Assuming the response contains user information with an 'id' field
      const userData = await response.json();
      provider = userData.id;
    } catch (error) {
      console.error(error);
      setError('Token validation failed. Please log in again.');
    } finally {
      if (provider) {
        setGlobalProvider(provider);
      }
    }
  };

  useEffect(() => {
    validate();
  }, []);

  return props.children(globalProvider, error);
};

export default AzureProvider;

In this modified AzureProvider component:

We use async/await it to perform token validation.
We check for a token localStorage and handle validation errors.
We set the provider and error states as appropriate.
We passed both provider and error values to the children via props.children.

Now, you can use the AzureProvider as shown in your App component:

import React from 'react';
import AzureProvider from './AzureProvider';

class App extends React.Component {
  render() {
    return (
      <div className="App">
        <h1>Welcome to My React App</h1>
        <AzureProvider>
          {(provider, error) => {
            if (error) {
              return <p style={{ color: "red" }}>{error}</p>;
            }
            if (provider) {
              return <Component provider={provider} />; // Replace 'Component' with the actual name of your child component
            }
            return <p>Loading</p>;
          }}
        </AzureProvider>
      </div>
    );
  }
}

export default App;

Here, we render a function as a child within the AzureProvider, which receives both the provider and error values and decides what to render based on the outcome of the token validation.

The Render Props pattern is a powerful tool for sharing data and functionality in your React components, making your code cleaner, more reusable, and more adaptable. So, whether you’re displaying the current date or managing user authentication, Render Props is your go-to pattern in the React kitchen.

Conclusion

In this guide, we’ve explored the Render Props pattern in React, a flexible and powerful approach to sharing data and functionality between components. We began with a simple example of displaying the current date and extended it to a real-world scenario of user token validation. With Render Props, you can create more organized, reusable, and efficient components in your React applications.

When to Use the Render Props Pattern:

Customization: Use Render Props when you need to customize the rendering of a component based on some data or functionality.
Data Sharing: It’s ideal for sharing data or behavior between components in a clean and maintainable way.
Reusability: Employ Render Props to make your components more reusable, as they can adapt to different use cases.
Flexibility: Choose this pattern when you want a flexible and versatile method for component composition.

When to Avoid the Render Props Pattern:

Simplicity: If your data-sharing needs are straightforward, and you don’t require customization, using the Render Props pattern might add unnecessary complexity to your code.
Overuse: Avoid overusing Render Props in situations where simpler solutions like prop drilling or context API suffice.
Nesting Complexity: Be cautious when nesting multiple components with Render Props, as it can make your code harder to maintain and understand.

In essence, the Render Props pattern is a fantastic tool for enhancing the reusability and flexibility of your React components. However, like any tool, it should be used judiciously, considering the complexity and requirements of your specific project. So, keep it in your toolkit and apply it where it fits best, ensuring a seamless and efficient development experience in your React applications.

Happy coding, and keep React-ing in style! 🚀💻

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开源日报第1088期：draw.io编辑器：《drawio-desktop》