# start

## Description

* Create a composite bundle out of multiple MiniApps and start the react-native local packager to serve this bundle so that it can be loaded within the native host application  

## Syntax

`ern start`

**Note**

If you do not pass an argument to this command, you are prompted to select a native application version from the Cauldron. The command uses whatever MiniApp versions are curently declared in this native application version container to launch the command.

**Options**

`--baseComposite <compositePath>`

* Git or File System path, to the custom Composite repository (refer to the \[custom Composite] documentation for more information).

`--descriptor/-d <descriptor>`

* Target a specific native application version, associated to the provided *complete native application descriptor*. &#x20;
* This option uses whatever MiniApp versions are currently declared in this native application version container to launch the command. &#x20;

`--miniapps/-m <miniapps>`

* Specify one or more MiniApps to launch this command &#x20;
* The command packages all the provided MiniApps in a composite bundle and starts the react-native packager. &#x20;
* You can use any valid Yarn package descriptor for the MiniApps provided to this command, including Git and other file system path schemes. &#x20;

`--jsApiImpls`

* Specify one or more JS API Implementations to include

`--watchNodeModules/-w <nodemodules>`

* A list of one or more directory name(s) from node\_modules that should be watched for changes.

`--extraJsDependencies/-e <jsdependencies>`

* Additional JavaScript dependencies to add to the composite JavaScript bundle.

`--disableBinaryStore`

* Setting this option will bypass retrieval and installation of the binary from the Binary Store. &#x20;
* It can be useful in case you want to use `ern start` command in conjunction with your own mobile application native binary, build locally on your workstation or retrieved from a specific location.

**Platform Specific Options**

`Android`

`--packageName/-p <packagename>`

* Android application package name to avoid conflict with the names of classes or interfaces.

`--activityName/-a <activity name>`

* Specify Android Activity to launch.

`iOS` `--bundleId/-b`

* iOS Bundle Identifier unique to your app.

## Remarks

* This command can be used to package multiple MiniApps inside a single composite bundle and automatically start the react-native local packager to serve this bundle. &#x20;
* Use this command when you need to launch and develop or debug your MiniApps from within a native host application which contains other MiniApps along with your MiniApp. &#x20;
* This command works with the `ern link` command. For additional information, see the documentation for the `ern link` command. &#x20;

## Related commands

[ern link](https://native.electrode.io/v0.31/cli-commands/link) | Link to a MiniApp directory

\[custom Composite]: ./platform-parts/composite/index.md