1、基本准备

卸载本地的ionic2，重装ionic3，更新package.json包，重新npm install（或者cnpm install）。

2、升级过程中遇到的问题

报错： Error: Cannot read property 'filter' of undefined
报错情况：

[12:44:35]  ionic-app-scripts 1.3.0
[12:44:35]  watch started ...
[12:44:35]  build dev started ...
[12:44:35]  clean started ...
[12:44:35]  clean finished in 1 ms
[12:44:35]  copy started ...
[12:44:35]  transpile started ...
[12:44:38]  transpile finished in 3.13 s
[12:44:38]  preprocess started ...
[12:44:38]  deeplinks started ...
[12:44:38]  ionic-app-script task: "serve"
[12:44:38]  Error: Cannot read property 'filter' of undefined
Error: Cannot read property 'filter' of undefined
    at new BuildError (/Users/bodhi/Projects/snapshare/node_modules/@ionic/app-scripts/dist/util/errors.js:16:28)
...

查找原因：是app.module.ts文件里的@NgModule出现了问题。
解决方法：先需要修改app.module.ts文件
imports里面一定要导入BrowserModule。

报错：webpackJsonp is not defined
报错情况：

图片.png

查找原因：缺少文件文件vendor.js的引用
解决方法：修改index.js文件

<script src="build/polyfills.js"></script>
<script src="build/vendor.js"></script> // 如果没有是需要新添加的
<script src="build/main.js"></script>

报错：No Provider for setting
报错情况：

图片.png

查找原因：没有在app.module.ts中的providers中注册
解决办法：

@NgModule({
  declarations: [
    AppComponent,
  ],
  imports: [
    Modules,
    BrowserModule,
    IonicModule.forRoot(AppComponent, {
    }),
    TranslateModule.forRoot({
      loader: {
        provide: TranslateLoader,
        useFactory: (createTranslateLoader),
        deps: [Http]
      }
    }),
  ],
  bootstrap: [IonicApp],
  entryComponents: [
    AppComponent,
  ],
  providers: [
    { provide: ErrorHandler, useClass: IonicErrorHandler },
    Api,
    Common,
    Settings,
    InAppBrowser,
    SplashScreen
  ]
})

报警告：Unused Import
解决办法：
在项目根目录找到 tslint.json 文件，查找no-duplicate-variable和no-unused-variable属性改为false即可。

"rules": {
    "no-duplicate-variable": true,
    "no-unused-variable": [
      false
    ]
  }