Switch to using a map of devices rather than an array

Author: chrisbianca

README.md

@@ -53,7 +53,11 @@ The structure of this Document is as follows:
 
 ```
 {
-  devices: Device[],
+  devices: {
+    deviceId1: Device,
+    deviceId2: Device,
+    ...
+  },
   userId: string,
 }
 ```
@@ -62,11 +66,12 @@ A `Device` object contains the following:
 
 ```
 {
-  deviceId: string, // The browser name and version
+  deviceId: string, // A randomly generated ID
   fcmToken: string, // The FCM token
-  name: 'Unknown',  // Web browser's do not provide a name field
+  name: string,     // The browser name
   os: string,       // The OS of the device
-  type: 'Web'
+  type: 'Web',
+  userAgent: string // The browser user agent string
 }
 ```
 
@@ -87,7 +92,7 @@ Returns a `DeviceStore`.
 
 Indicate to the DeviceStore that the user is about to sign out, and the current device token should be removed.
 
-This cannot be done automatically with `onAuthStateChanged` as the user won't have permission to remove the token from Firestore as they are already signed out by this point and the Cloud Firestore security rules will prevent the database deletion.
+This can't be done automatically with `onAuthStateChanged` as the user is already signed out at this point. This means the Cloud Firestore security rules will prevent the database deletion as they no longer have the correct user permissions to remove the token.
 
 #### `DeviceStore.subscribe(): Promise<void>`
 

package.json

@@ -22,9 +22,11 @@
   },
   "homepage": "https://github.com/csfrequency/firebase-device-store-js-sdk#readme",
   "dependencies": {
-    "detect-browser": "^4.5.0"
+    "detect-browser": "^4.5.0",
+    "nanoid": "^2.0.2"
   },
   "devDependencies": {
+    "@types/nanoid": "^2.0.0",
     "firebase": "^5.9.4",
     "prettier": "^1.17.0",
     "rimraf": "^2.6.3",

src/index.ts

@@ -1,12 +1,21 @@
 import { detect } from 'detect-browser';
 import * as firebase from 'firebase';
+import nanoid from 'nanoid';
 
 type Device = {
   deviceId: string;
   fcmToken: string;
   name: string;
   os: string;
   type: 'Android' | 'iOS' | 'Web';
+  userAgent?: string;
+};
+
+type Devices = { [deviceId: string]: Device };
+
+type UserDevices = {
+  devices: Devices;
+  userId: string;
 };
 
 interface DeviceStore {
@@ -138,20 +147,19 @@ const addToken = (
     const doc = await transaction.get(docRef);
 
     if (doc.exists) {
-      const devices: Device[] = doc.data().devices || [];
-      // Add the new device if it doesn't already exist
-      if (!devices.find(device => device.fcmToken === token)) {
-        devices.push(createDevice(token));
-      }
+      const devices = getDevices(doc);
+
+      // Check if a device already matches the FCM token, or generate a new one
+      const deviceId = findDeviceId(devices, token) || generateDeviceId();
+      // Set the device information
+      devices[deviceId] = createDevice(deviceId, token);
       // Update the document
       return transaction.update(docRef, {
         devices,
       });
     } else {
-      return transaction.set(docRef, {
-        devices: [createDevice(token)],
-        userId,
-      });
+      const userDevices = createUserDevices(userId, token);
+      return transaction.set(docRef, userDevices);
     }
   });
 };
@@ -168,21 +176,21 @@ const deleteToken = (
     const doc = await transaction.get(docRef);
 
     if (doc.exists) {
-      const devices: Device[] = doc.data().devices || [];
-      // Remove the old device
-      const updatedDevices = devices.filter(
-        device => device.fcmToken !== token
-      );
-      // Update the document
-      return transaction.update(docRef, {
-        devices: updatedDevices,
-      });
-    } else {
-      return transaction.set(docRef, {
-        devices: [],
-        userId,
-      });
+      const devices = getDevices(doc);
+
+      // Find the device that matches the FCM token
+      const deviceId = findDeviceId(devices, token);
+
+      // If there is a matching device, remove it and update the document
+      if (deviceId) {
+        delete devices[deviceId];
+      }
+      return transaction.update(docRef, 'devices', devices);
     }
+
+    // Firestore requires that every document read in a transaction must also
+    // be written
+    return transaction.set(docRef, undefined);
   });
 };
 
@@ -199,47 +207,79 @@ const updateToken = (
     const doc = await transaction.get(docRef);
 
     if (doc.exists) {
-      const devices: Device[] = doc.data().devices || [];
-      let updatedDevices = devices;
-      // Remove the old device
+      const devices = getDevices(doc);
+      const updatedDevices: Devices = {
+        ...devices,
+      };
+
+      // If an old token is specified, find the device that matches the token
       if (oldToken) {
-        updatedDevices = devices.filter(device => device.fcmToken !== oldToken);
+        const deviceId = findDeviceId(devices, oldToken);
+        // If there is a matching device, then remove it
+        if (deviceId) {
+          delete updatedDevices[deviceId];
+        }
       }
-      // Add the new device if it doesn't already exist
+
+      // If a new token is specified, then add the device
       if (newToken) {
-        if (!updatedDevices.find(device => device.fcmToken === newToken)) {
-          updatedDevices.push(createDevice(newToken));
-        }
+        const deviceId = generateDeviceId();
+        updatedDevices[deviceId] = createDevice(deviceId, newToken);
       }
+
       // Update the document
       return transaction.update(docRef, {
         devices: updatedDevices,
       });
-    } else if (newToken) {
-      return transaction.set(docRef, {
-        devices: [createDevice(newToken)],
-        userId,
-      });
     } else {
-      return transaction.set(docRef, {
-        devices: [],
-        userId,
-      });
+      const userDevices = createUserDevices(userId, newToken);
+      return transaction.set(docRef, userDevices);
     }
   });
 };
 
-const createDevice = (fcmToken: string): Device => {
+const createDevice = (deviceId: string, fcmToken: string): Device => {
   const browser = detect();
   return {
-    deviceId: window.navigator.userAgent,
+    deviceId,
     fcmToken,
     name: browser.name.charAt(0).toUpperCase() + browser.name.slice(1),
     os: browser.os,
     type: 'Web',
+    userAgent: window.navigator.userAgent,
+  };
+};
+
+const createUserDevices = (
+  userId: string,
+  fcmToken: string | void
+): UserDevices => {
+  const deviceId = generateDeviceId();
+  return {
+    devices: fcmToken
+      ? {
+          [deviceId]: createDevice(deviceId, fcmToken),
+        }
+      : {},
+    userId,
   };
 };
 
+const findDeviceId = (devices: Devices, token: string): string | void => {
+  return Object.keys(devices).find(deviceId => {
+    const device = devices[deviceId];
+    return device.fcmToken === token;
+  });
+};
+
+const generateDeviceId = (): string => {
+  return nanoid();
+};
+
+const getDevices = (doc: firebase.firestore.DocumentSnapshot): Devices => {
+  return doc.data().devices || {};
+};
+
 const userRef = (
   firestore: firebase.firestore.Firestore,
   collectionPath: string,

tsconfig.json

@@ -1,6 +1,7 @@
 {
   "compileOnSave": false,
   "compilerOptions": {
+    "allowSyntheticDefaultImports": true,
     "declaration": true,
     "importHelpers": true,
     "lib": ["es2017", "es2015", "dom"],

yarn.lock

@@ -151,6 +151,13 @@
   resolved "https://registry.yarnpkg.com/@types/estree/-/estree-0.0.39.tgz#e177e699ee1b8c22d23174caaa7422644389509f"
   integrity sha512-EYNwp3bU+98cpU4lAWYYL7Zz+2gryWH1qbdDTidVd6hkiR6weksdbMadyXKXNPEkQFhXM+hVO9ZygomHXp+AIw==
 
+"@types/nanoid@^2.0.0":
+  version "2.0.0"
+  resolved "https://registry.yarnpkg.com/@types/nanoid/-/nanoid-2.0.0.tgz#b59002c475e6dfcc26e67ba563ff61b512e5ebf8"
+  integrity sha512-NtwPHfAyU3IDXdKAB2OMPpAauHBg9gUjpOYr3FAzI84D70nWdS8k5mryteLvT/s1ACeAFAkGg132/XJVN4qx/w==
+  dependencies:
+    "@types/node" "*"
+
 "@types/node@*", "@types/node@^11.13.4":
   version "11.13.5"
   resolved "https://registry.yarnpkg.com/@types/node/-/node-11.13.5.tgz#266564afa8a6a09dc778dfacc703ed3f09c80516"
@@ -1044,6 +1051,11 @@ nan@^2.0.0:
   resolved "https://registry.yarnpkg.com/nan/-/nan-2.13.2.tgz#f51dc7ae66ba7d5d55e1e6d4d8092e802c9aefe7"
   integrity sha512-TghvYc72wlMGMVMluVo9WRJc0mB8KxxF/gZ4YYFy7V2ZQX9l7rgbPg7vjS9mt6U5HXODVFVI2bOduCzwOMv/lw==
 
+nanoid@^2.0.2:
+  version "2.0.2"
+  resolved "https://registry.yarnpkg.com/nanoid/-/nanoid-2.0.2.tgz#2163edc84828cd42f9b8e4578979a4b5ffc1bb18"
+  integrity sha512-X4yQ8VHoFvHcykGunT2Jxrsm1c4vH5UKtau7LLJYXO1istCRE3jD8JxDyGCzN+h7dpWBCvWaSYgloRuphKRqUQ==
+
 nanomatch@^1.2.9:
   version "1.2.13"
   resolved "https://registry.yarnpkg.com/nanomatch/-/nanomatch-1.2.13.tgz#b87a8aa4fc0de8fe6be88895b38983ff265bd119"