错误信息：
D:\project\eyeshot\eyeshot\Source3>ionic cordova run android
> ionic-app-scripts build --target cordova --platform android
[07:23:31] ionic-app-scripts 3.2.0
[07:23:31] build dev started ...
[07:23:31] clean started ...
[07:23:31] clean finished in 5 ms
[07:23:31] copy started ...
[07:23:32] deeplinks started ...
[07:23:32] deeplinks finished in 320 ms
[07:23:32] transpile started ...
[07:23:37] typescript: ...ject/eyeshot/eyeshot/Source3/node_modules/@angular/fire/firebase.app.module.d.ts, line: 2
Module '"D:/project/eyeshot/eyeshot/Source3/node_modules/firebase/index"' has no exported member
'functions'.
L1: import { InjectionToken } from '@angular/core';
L2: import { app, auth, database, firestore, functions, messaging, storage } from 'firebase/app';
L3: export declare type FirebaseOptions = {
[07:23:37] ionic-app-script task: "build"
[07:23:37] Error: Failed to transpile program
Error: Failed to transpile program
at new BuildError (D:\project\eyeshot\eyeshot\Source3\node_modules\@ionic\app-scripts\dist\util\errors.js:16:28)
at D:\project\eyeshot\eyeshot\Source3\node_modules\@ionic\app-scripts\dist\transpile.js:159:20
at new Promise (<anonymous>)
at transpileWorker (D:\project\eyeshot\eyeshot\Source3\node_modules\@ionic\app-scripts\dist\transpile.js:107:12)
at Object.transpile (D:\project\eyeshot\eyeshot\Source3\node_modules\@ionic\app-scripts\dist\transpile.js:64:12)
at D:\project\eyeshot\eyeshot\Source3\node_modules\@ionic\app-scripts\dist\build.js:109:82
......
解决办法：
修改package.json文件，
把"firebase": "^4.6.1",改为"firebase": "^5.0.0"