ReferenceError: document is not defined. Service worker. Workbox - service-worker

Question

I'm learning how to write code of service worker and stuck with the error "ReferenceError: document is not defined" in my app.js file. I'm using workbox library with InjectManifest mode. I think the problem in the webpack.config.js, because when I delete InjectManifest in webpack.config.js the error disappears.
My webpack.config.js
const path = require('path');
const webpack = require('webpack');
const HtmlWebPackPlugin = require('html-webpack-plugin');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');
const CssMinimizerPlugin = require('css-minimizer-webpack-plugin');
const {InjectManifest} = require('workbox-webpack-plugin');
module.exports = {
entry: './src/index.js',
output: {
path: path.resolve(__dirname, 'dist'),
},
module: {
rules: [
{
test: /\.js$/,
exclude: /node_modules/,
use: {
loader: 'babel-loader',
},
},
{
test: /\.html$/i,
use: [
{
loader: 'html-loader',
},
],
},
{
test: /\.css$/,
use: [
MiniCssExtractPlugin.loader, 'css-loader',
],
},
{
test: /\.(png|jpg|gif)$/i,
use: [
{
loader: 'url-loader',
options: {
limit: 8192,
},
},
],
},
],
},
optimization: {
minimize: true,
minimizer: [
new CssMinimizerPlugin(),
],
},
plugins: [
new HtmlWebPackPlugin({
template: './src/index.html',
filename: './index.html',
}),
new MiniCssExtractPlugin({
filename: '[name].css',
chunkFilename: '[id].css',
}),
new InjectManifest({
swSrc: './src/js/service.worker.js',
swDest: 'service.worker.js',
}),
],
};
My service.worker.js file:
import { precacheAndRoute } from 'workbox-precaching/precacheAndRoute';
import { cinemaNews } from './cinemaNews';
import { url } from './app';
precacheAndRoute(self.__WB_MANIFEST);
const CACHE_NAME = 'v1';
const responseCache = new Response(JSON.stringify(cinemaNews));
self.addEventListener('install', (evt) => {
console.log('install')
evt.waitUntil((async () => {
console.log('install waitUntil')
const cache = await caches.open(CACHE_NAME);
await cache.put(url, responseCache);
await self.skipWaiting();
})());
});
self.addEventListener('activate', (evt) => {
console.log('activate')
evt.waitUntil(self.clients.claim());
});
self.addEventListener('fetch', (evt) => {
console.log('sw fetch')
const requestUrl = new URL(evt.request.url);
if (!requestUrl.pathname.startsWith('/news')) return;
evt.respondWith((async () => {
console.log('respondWith')
const cache = await caches.open(CACHE_NAME);
const cachedResponse = await cache.match(evt.request);
return cachedResponse;
})());
evt.waitUntil((async () => {
console.log('waitUntil');
const response = await fetch(evt.request.url);
const client = await clients.get(evt.clientId);
let json = await response.json();
client.postMessage(json);
})());
});

Answer 1

This statement:
import { url } from './app';
appears to be triggering the issue, as there must be code inside of your app.js that is executed via that import, and which assumes that document will be defined. (It's not defined inside of the ServiceWorkerGlobalScope.)
Based on how you're using the export, I'm assuming that it's just a string constant containing a shared URL that you want to use from both your main web app and your service worker. Assuming that's the case, the easiest thing to do would be to refactor your modules that there's a constants.js (or some similar name) module that only exports your string constants, and doesn't try to run any code that references document. You can then import the constant from either your web app or the service worker without issue.
// constants.js
export const url = '/path/to/url';
// service-worker.js
import {url} from './constants';
// do something with url
// app.js
import {url} from './constants';
// do something with url