如何将事件侦听器添加到 create-react-app 默认 sw.js 文件

Question

我想使用 Create-React-App 模块的默认 service-worker (sw.js) 文件。

sw.js 文件如下代码：

const isLocalhost = Boolean(
  window.location.hostname === 'localhost' ||
    window.location.hostname === '[::1]' ||
    window.location.hostname.match(
      /^127(?:\.(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)){3}$/
    )
);

export function register(config) {
  if (process.env.NODE_ENV === 'production' && 'serviceWorker' in navigator) {
    console.log('[Service Worker] Service Worker Registered!');
    const publicUrl = new URL(process.env.PUBLIC_URL, window.location.href);
    if (publicUrl.origin !== window.location.origin) {
      return;
    }

    window.addEventListener('load', () => {
      const swUrl = `${process.env.PUBLIC_URL}/service-worker.js`;

      if (isLocalhost) {
        checkValidServiceWorker(swUrl, config);

        navigator.serviceWorker.ready.then(() => {
          console.log(
            'hello'
          );
        });
      } else {
        registerValidSW(swUrl, config);
      }
    });

  }
}

function registerValidSW(swUrl, config) {
  navigator.serviceWorker
    .register(swUrl)
    .then(registration => {
      registration.onupdatefound = () => {
        const installingWorker = registration.installing;
        if (installingWorker == null) {
          return;
        }
        installingWorker.onstatechange = () => {
          if (installingWorker.state === 'installed') {
            if (navigator.serviceWorker.controller) {
              console.log(
                'link'
              );

              if (config && config.onUpdate) {
                config.onUpdate(registration);
              }
            } else {
              console.log('Content is cached for offline use.');

              if (config && config.onSuccess) {
                config.onSuccess(registration);
              }
            }
          }
        };
      };
    })
    .catch(error => {
      console.error('Error during service worker registration:', error);
    });
}

function checkValidServiceWorker(swUrl, config) {
  fetch(swUrl)
    .then(response => {
      const contentType = response.headers.get('content-type');
      if (
        response.status === 404 ||
        (contentType != null && contentType.indexOf('javascript') === -1)
      ) {

        navigator.serviceWorker.ready.then(registration => {
          registration.unregister().then(() => {
            window.location.reload();
          });
        });
      } else {
        registerValidSW(swUrl, config);
      }
    })
    .catch(() => {
      console.log(
        'No internet connection found. App is running in offline mode.'
      );
    });
}

export function unregister() {
  if ('serviceWorker' in navigator) {
    navigator.serviceWorker.ready.then(registration => {
      registration.unregister();
    });
  }
}

我想要在这个文件中添加更多的事件监听器，我已经尝试了上面代码的不同部分来添加监听器，但是它不起作用！作为一个例子，我添加了以下内容，但我不知道它应该放在哪里才能正常工作：

window.addEventListener('fetch', (e){
    console.log('[service worker] fetch')
})

其他事件有install、activate、beforeinstallprompt等。

我问这个问题的主要目的是了解如何将安装横幅添加到我的 react 项目中！

Answer 1

您不能在不弹出的情况下修改 create-react-app 中生成的 service worker 文件。作为一种解决方法，您可以创建一个 sw-epilog.js 文件，在其中添加所有 service worker 特定代码并在package.json 将该文件附加到生成的服务工作者文件中，如https://github.com/facebook/create-react-app/issues/5890#issuecomment-450915616 中所述

我有一个要点来证明这一点https://gist.github.com/khaledosman/de3535c8873831153efdf6c10a4b4080查看最后两个文件

// sw-epilog.js
// Add a listener to receive messages from clients
self.addEventListener('message', function(event) {
  // Force SW upgrade (activation of new installed SW version)
  if ( event.data === 'skipWaiting' ) {
    self.skipWaiting();
  }
});

//package.json
"scripts": {
  "build": "rm -rf build/ && react-scripts build && npm run-script sw-epilog",
  "sw-epilog": "cat src/sw-epilog.js >> build/service-worker.js",
},

对于完整的实现，您还可以查看https://github.com/khaledosman/create-react-pwa