Firebase in a chrome extension

Adding firebase/firestore to chrome extension

based on stackoverflow Add Cloud firestore library to chrome extension, content_scripts

in chrome extension manifest file manifest.json add firebase-app.js (https://www.gstatic.com/firebasejs/7.5.0/firebase-app.js) and firebase-firestore.js(https://www.gstatic.com/firebasejs/7.5.0/firebase-firestore.js) as follows

...
"content_scripts": [
{
"matches": [
"https://www.wsj.com/*"
],
"js": [
"firebasejs/7.5.0/firebase-app.js",
"firebasejs/7.5.0/firebase-firestore.js",
...

As well as

...
"content_security_policy":"script-src 'self' https://www.gstatic.com/ https://*.firebaseio.com https://www.googleapis.com; object-src 'self'"
}

then in your extension code you can just initialise firebase as usual eg

const firebaseConfig = {
apiKey: "XXX",
authDomain: "XXX",
databaseURL: "XXX",
projectId: "XXX",
storageBucket: "XXX",
messagingSenderId: "XXX",
appId: "XXX",
measurementId: "XXX"
};
firebase.initializeApp(firebaseConfig);
const db = firebase.firestore();
// do something with firebase/firestore