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A fragile weaving of various modules together to convince the Firestore web SDK to use persistence in an un-ejected Expo app.
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/* | |
expo-firestore-persistence-hack | |
A fragile weaving of various modules together to convince the Firestore | |
web SDK to use persistence in an un-ejected Expo app. | |
To use, first: | |
``` | |
$ expo install expo-sqlite | |
$ yarn add indexeddbshim | |
``` | |
Then add the contents of this file to `expo-firestore-persistence-hack.js` | |
in your project, and import it very early (likely in App.js). After this is | |
imported, you can ask firestore to enable persistence: | |
`firebase.firestore().enablePersistence()` | |
The bulk of the work is done by indexeddbshim, which provides an IndexedDB | |
implementation on top of WebSQL. See the comments below above each hunk of | |
code to understand how hacky this all is. | |
*/ | |
import { SQLite } from "expo-sqlite"; | |
// Hack 1: The SQLite module from Expo is nominally | |
// WebSQL compatible. Let's just have the IndexedDB shim | |
// use it! | |
window.openDatabase = SQLite.openDatabase; | |
// Hack 2: indexeddbshim will try to examine navigator.userAgent | |
// if navigator exists. In React Native, it does, but has no | |
// userAgent set. Set one here to avoid a crash. | |
navigator.userAgent = "React-Native"; | |
// Hack 3: Initialize indexeddbshim with origin checks disabled, | |
// cause they'll fail on our platform (and don't quite make sense.) | |
// (Do not change this to an import, cause that will get hoisted above | |
// our userAgent hack above.) | |
const setGlobalVars = require("./node_modules/indexeddbshim/dist/indexeddbshim-noninvasive"); | |
setGlobalVars(window, { checkOrigin: false }); | |
// Hack 4: Firestore persistence really wants to use localStorage | |
// to communicate between tabs. We don't really care about | |
// communicating between tabs - everything will be in the same | |
// process. However, Firestore needs something. So we'll give it | |
// a really weak, fake, in-memory localStorage. (Persisted storage | |
// will go through IndexedDB and into SQLite, on disk.) | |
window.__localStorageStore = {}; | |
window.localStorage = { | |
getItem: function(key) { | |
return window.__localStorageStore[key]; | |
}, | |
setItem: function(key, value) { | |
window.__localStorageStore[key] = value; | |
}, | |
removeItem: function(key) { | |
delete window.__localStorageStore[key]; | |
}, | |
clear: function() { | |
window.__localStorageStore = {}; | |
}, | |
key: function(i) { | |
// Ever since ES6, the order of keys returned here is | |
// stable 🤞 | |
Object.keys(window.__localStorageStore)[i]; | |
} | |
}; | |
// You should now be able to initialize Firebase, and call | |
// firebase.firestore().enablePersistence() | |
// | |
// YMMV! YOLO! |
Hello everyone, now 2023 but I still need this gist or this lib https://github.com/nandorojo/expo-firestore-offline-persistence to make firebase js lib have persistence. Because I'm still using Expo Go and firebase js to develop React Native app
But I can't install indexeddbshim
Both the latest version or 6.6.0 require node lib
error /Users/minhdrminh/Projects/ExpoTree/node_modules/sqlite3: Command failed.
Exit code: 1
Command: node-pre-gyp install --fallback-to-build
How can I fix it? any idea?
Thanks for your help
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At this point, I recommend using an Expo dev client with React Native Firebase.