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@loopback/example-lb3-application

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Readme

@loopback/example-lb3-application

This example demonstrates how to mount your existing LoopBack 3 application in a new LoopBack 4 project.

Tutorial

Create a new LoopBack 4 project using lb4 app.
```
$ lb4 app
```
Fill out the prompts as they fit your project and leave all features enabled.

Create a new directory lb3app from the root of your LoopBack 4 application and copy your existing LoopBack 3 application there. You should end up with the following directory layout:

lb3app/
  # LoopBack 3 application in JavaScript
  common/
    models/
      # LB3 model files
  server/
    boot/
      # LB3 boot scripts
public/
  # front-end assets (LB4 way)
src/
  # LoopBack 4 application in TypeScript

Move LB3 dependencies to the main package.json file and remove lb3app/package.json, lb3app/node_modules/, andlb3app/package-lock.json, if it exists. Typically you will need to add the following entries, plus any connectors or components you are using in your LB3 application.
```
{
  "compression": "^1.7.4",
  "cors": "^2.8.5",
  "helmet": "^3.16.0",
  "loopback": "^3.25.1",
  "loopback-boot": "^3.3.0"
}
```
Note: make sure to use loopback-boot@3.2.1 or higher.

Run npm install from the root of your LB4 project to install the LB3 dependencies.
Disable error handling in your LB3 app, leave it for the new LB4 app.
- Remove lb3app/server/middleware.development.json
- Edit lb3app/server/middleware.json and remove the following two entries:
  - final >> loopback#urlNotFound
  - final:after >> strong-error-handler
- Remove strong-error-handler from package.json dependencies.
- In lb3app/server/config.json, if "handleErrors": false is in remoting, move it to rest.
Move your front-end files from lb3app/client to public/ directory and disable static assets in your LB3 app by removing the following entry in lb3app/server/middleware.json:
- files >> loopback#static
Also remove lb3app/server/boot/root.js, since the main page will be served by the LoopBack 4 project.
Remove lb3app/server/component-config.json to disable LoopBack 3's explorer. The LoopBack 4 explorer will be used instead.
Install and configure @loopback/booter-lb3app to boot and mount the LB3 application:
1. npm install --save @loopback/booter-lb3app
2. Import the component at the top of your src/application.ts file.
```
import {Lb3AppBooterComponent} from '@loopback/booter-lb3app';
```
3. Register the component in Application's constructor:
```
this.component(Lb3AppBooterComponent);
```

Try it out

Start the new LB4 application

```sh
$ npm start
Server is running at http://127.0.0.1:3000
```

Open the URL printed to console to view your front-end served from public directory or go to http://127.0.0.1:3000/explorer to explore the REST API.

Need help?

Check out our Gitter channel and ask for help with this tutorial.

Bugs/Feedback

Open an issue in loopback-next and we'll take a look.

Contributions

Tests

Run npm test from the root folder.

Contributors

See all contributors.

License

MIT