Metro CLI Options

The metro command line runner has a number of useful options. You can run metro --help to view all available options. Here is a brief overview:

`build <entry>`

Generates a JavaScript bundle containing the specified entrypoint and its descendants.

Option	Alias	Description	Value
`out`	`O`	File name where to store the output (required)	String
`platform`	`p`	Which platform to bundle for (e.g. `web`, `android`, `ios`)	String
`minify`	`z`	Whether Metro should minify the bundle	Boolean
`dev`	`g`	Create a development build, in which `__DEV__` is `true`	Boolean
`config`	`c`	Location of the `metro.config.js` to use	String
`max-workers`	`j`	The number of workers Metro should parallelize the transformer on. Overrides `maxWorkers` which defaults to a number based on `os.availableParallelism()`	Number
`project-roots`	`P`	Accepted, but has no effect	Array
`source-map`		Whether Metro should generate source maps	Boolean
`source-map-url`		URL where the source map can be found	String
`legacy-bundler`		Accepted, but has no effect	Boolean
`resolver-option`		Custom resolver options of the form `key=value`	Array
`transform-option`	`transformer-option`	Custom transform options of the form `key=value`	Array
`reset-cache`		Deprecated. Clears Metro's caches before building, like `resetCache`	Boolean
`output-type`	`t`	Accepted, but has no effect	String

Alias: start

Starts Metro on the given port, building bundles on the fly. Restarts the server when the config file changes.

Option	Alias	Description	Value
`host`	`h`	Host to listen on. Defaults to `localhost`	String
`port`	`p`	Port to listen on. Defaults to `8081`, overriding `server.port`	Number
`config`	`c`	Location of the `metro.config.js` to use	String
`max-workers`	`j`	The number of workers Metro should parallelize the transformer on. Overrides `maxWorkers` which defaults to a number based on `os.availableParallelism()`	Number
`secure-server-options`	`s`	Options for the HTTPS server, using dot notation (e.g. `-s.cert="$(cat path/to/cert)" -s.key="$(cat path/to/key)"`)	Object
`secure`		Deprecated. Serve over HTTPS. Use `secure-server-options` instead	Boolean
`secure-key`		Deprecated. Path to the key file for HTTPS when `secure` is set	String
`secure-cert`		Deprecated. Path to the cert file for HTTPS when `secure` is set	String
`reset-cache`		Deprecated. Clears Metro's caches on startup, like `resetCache`	Boolean
`project-roots`	`P`	Accepted, but has no effect	Array
`hmr-enabled`	`hmr`	Accepted, but has no effect	Boolean

List all dependencies that will be bundled for a given entry point.

Option	Description
`entry-file`	Absolute path to the root JS file. This can also be given as the first positional arg.
`output`	File name where to store the output, ex. /tmp/dependencies.txt
`platform`	The platform extension used for selecting modules
`transformer`	Specify a custom transformer to be used
`max-workers`	Specifies the maximum number of workers the worker-pool will spawn for transforming files. Overrides `maxWorkers` which defaults to a number based on `os.availableParallelism()`.
`dev`	If false, skip all dev-only code path. Defaults to `true`
`verbose`	Enables logging. Defaults to `false`