Makes the Metro CLI commands injectable

Summary: This diff makes the Metro CLI commands injectable into any Yargs object, so that we can override various aspects of it, add extra commands, etc.

Reviewed By: davidaurelio

Differential Revision: D6988250

fbshipit-source-id: 217c661e4c1b05282b6cdbf4d745d1b29f5cbbe0

packages/metro/src/cli.js

@@ -14,4 +14,6 @@
 
 const yargs = require('yargs');
 
-yargs.demandCommand(1).commandDir(`${__dirname}/commands`).argv;
+const {attachMetroCli} = require('./index');
+
+attachMetroCli(yargs.demandCommand(1)).argv;

packages/metro/src/commands/build.js

@@ -18,76 +18,81 @@ const {Terminal} = require('metro-core');
 
 import typeof Yargs from 'yargs';
 
-exports.command = 'build <entry>';
-
-exports.builder = (yargs: Yargs) => {
-  yargs.option('project-roots', {
-    alias: 'P',
-    type: 'string',
-    array: true,
-  });
-  yargs.option('out', {alias: 'O', type: 'string', demandOption: true});
-
-  yargs.option('platform', {alias: 'p', type: 'string'});
-  yargs.option('output-type', {alias: 't', type: 'string'});
-
-  yargs.option('max-workers', {alias: 'j', type: 'number'});
-
-  yargs.option('optimize', {alias: 'z', type: 'boolean'});
-  yargs.option('dev', {alias: 'g', type: 'boolean'});
-
-  yargs.option('source-map', {type: 'boolean'});
-  yargs.option('source-map-url', {type: 'string'});
-
-  yargs.option('legacy-bundler', {type: 'boolean'});
-
-  yargs.option('config', {alias: 'c', type: 'string'});
-
-  // Deprecated
-  yargs.option('reset-cache', {type: 'boolean', describe: null});
-};
-
 const term = new Terminal(process.stdout);
 const updateReporter = new TerminalReporter(term);
 
-// eslint-disable-next-line lint/no-unclear-flowtypes
-exports.handler = makeAsyncCommand(async (argv: any) => {
-  // $FlowFixMe: Flow + Promises don't work consistently https://fb.facebook.com/groups/flow/permalink/1772334656148475/
-  const config = await MetroApi.loadMetroConfig(argv.config);
+module.exports = () => ({
+  command: 'build <entry>',
 
-  if (argv.projectRoots) {
-    config.getProjectRoots = () => argv.projectRoots;
-  }
+  description:
+    'Generates a JavaScript bundle containing the specified entrypoint and its descendants',
 
-  await MetroApi.runBuild({
-    ...argv,
-    config,
-    onBegin: () => {
-      updateReporter.update({
-        buildID: '$',
-        type: 'bundle_build_started',
-        bundleDetails: {
-          entryFile: argv.O,
-          platform: argv.platform,
-          dev: !!argv.dev,
-          minify: !!argv.optimize,
-          bundleType: 'Bundle',
-        },
-      });
-    },
-    onProgress: (transformedFileCount, totalFileCount) => {
-      updateReporter.update({
-        buildID: '$',
-        type: 'bundle_transform_progressed_throttled',
-        transformedFileCount,
-        totalFileCount,
-      });
-    },
-    onComplete: () => {
-      updateReporter.update({
-        buildID: '$',
-        type: 'bundle_build_done',
-      });
-    },
-  });
+  builder: (yargs: Yargs) => {
+    yargs.option('project-roots', {
+      alias: 'P',
+      type: 'string',
+      array: true,
+    });
+    yargs.option('out', {alias: 'O', type: 'string', demandOption: true});
+
+    yargs.option('platform', {alias: 'p', type: 'string'});
+    yargs.option('output-type', {alias: 't', type: 'string'});
+
+    yargs.option('max-workers', {alias: 'j', type: 'number'});
+
+    yargs.option('optimize', {alias: 'z', type: 'boolean'});
+    yargs.option('dev', {alias: 'g', type: 'boolean'});
+
+    yargs.option('source-map', {type: 'boolean'});
+    yargs.option('source-map-url', {type: 'string'});
+
+    yargs.option('legacy-bundler', {type: 'boolean'});
+
+    yargs.option('config', {alias: 'c', type: 'string'});
+
+    // Deprecated
+    yargs.option('reset-cache', {type: 'boolean', describe: null});
+  },
+
+  // eslint-disable-next-line lint/no-unclear-flowtypes
+  handler: makeAsyncCommand(async (argv: any) => {
+    // $FlowFixMe: Flow + Promises don't work consistently https://fb.facebook.com/groups/flow/permalink/1772334656148475/
+    const config = await MetroApi.loadMetroConfig(argv.config);
+
+    if (argv.projectRoots) {
+      config.getProjectRoots = () => argv.projectRoots;
+    }
+
+    await MetroApi.runBuild({
+      ...argv,
+      config,
+      onBegin: () => {
+        updateReporter.update({
+          buildID: '$',
+          type: 'bundle_build_started',
+          bundleDetails: {
+            entryFile: argv.entry,
+            platform: argv.platform,
+            dev: !!argv.dev,
+            minify: !!argv.optimize,
+            bundleType: 'Bundle',
+          },
+        });
+      },
+      onProgress: (transformedFileCount, totalFileCount) => {
+        updateReporter.update({
+          buildID: '$',
+          type: 'bundle_transform_progressed_throttled',
+          transformedFileCount,
+          totalFileCount,
+        });
+      },
+      onComplete: () => {
+        updateReporter.update({
+          buildID: '$',
+          type: 'bundle_build_done',
+        });
+      },
+    });
+  }),
 });

packages/metro/src/commands/serve.js

@@ -17,70 +17,75 @@ const {promisify} = require('util');
 
 import typeof Yargs from 'yargs';
 
-exports.command = 'serve';
+module.exports = () => ({
+  command: 'serve',
 
-exports.builder = (yargs: Yargs) => {
-  yargs.option('project-roots', {
-    alias: 'P',
-    type: 'string',
-    array: true,
-  });
+  description:
+    'Starts a Metro server on the given port, building bundles on the fly',
 
-  yargs.option('host', {alias: 'h', type: 'string', default: 'localhost'});
-  yargs.option('port', {alias: 'p', type: 'number', default: 8080});
-
-  yargs.option('max-workers', {alias: 'j', type: 'number'});
-
-  yargs.option('secure', {type: 'boolean'});
-  yargs.option('secure-key', {type: 'string'});
-  yargs.option('secure-cert', {type: 'string'});
-
-  yargs.option('hmr-enabled', {alias: 'hmr', type: 'boolean'});
-
-  yargs.option('config', {alias: 'c', type: 'string'});
-
-  // Deprecated
-  yargs.option('reset-cache', {type: 'boolean', describe: null});
-};
-
-// eslint-disable-next-line lint/no-unclear-flowtypes
-exports.handler = makeAsyncCommand(async (argv: any) => {
-  let server = null;
-  let restarting = false;
-
-  async function restart() {
-    if (restarting) {
-      return;
-    } else {
-      restarting = true;
-    }
-
-    if (server) {
-      // eslint-disable-next-line no-console
-      console.log('Configuration changed. Restarting the server...');
-      await promisify(server.close).call(server);
-    }
-
-    // $FlowFixMe: Flow + Promises don't work consistently https://fb.facebook.com/groups/flow/permalink/1772334656148475/
-    const config = await MetroApi.loadMetroConfig(argv.config);
-
-    if (argv.projectRoots) {
-      config.getProjectRoots = () => argv.projectRoots;
-    }
-
-    server = await MetroApi.runServer({
-      ...argv,
-      config,
+  builder: (yargs: Yargs) => {
+    yargs.option('project-roots', {
+      alias: 'P',
+      type: 'string',
+      array: true,
     });
 
-    restarting = false;
-  }
+    yargs.option('host', {alias: 'h', type: 'string', default: 'localhost'});
+    yargs.option('port', {alias: 'p', type: 'number', default: 8080});
 
-  const metroConfigLocation = await MetroApi.findMetroConfig(argv.config);
+    yargs.option('max-workers', {alias: 'j', type: 'number'});
 
-  if (metroConfigLocation) {
-    await watchFile(metroConfigLocation, restart);
-  } else {
-    await restart();
-  }
+    yargs.option('secure', {type: 'boolean'});
+    yargs.option('secure-key', {type: 'string'});
+    yargs.option('secure-cert', {type: 'string'});
+
+    yargs.option('hmr-enabled', {alias: 'hmr', type: 'boolean'});
+
+    yargs.option('config', {alias: 'c', type: 'string'});
+
+    // Deprecated
+    yargs.option('reset-cache', {type: 'boolean', describe: null});
+  },
+
+  // eslint-disable-next-line lint/no-unclear-flowtypes
+  handler: makeAsyncCommand(async (argv: any) => {
+    let server = null;
+    let restarting = false;
+
+    async function restart() {
+      if (restarting) {
+        return;
+      } else {
+        restarting = true;
+      }
+
+      if (server) {
+        // eslint-disable-next-line no-console
+        console.log('Configuration changed. Restarting the server...');
+        await promisify(server.close).call(server);
+      }
+
+      // $FlowFixMe: Flow + Promises don't work consistently https://fb.facebook.com/groups/flow/permalink/1772334656148475/
+      const config = await MetroApi.loadMetroConfig(argv.config);
+
+      if (argv.projectRoots) {
+        config.getProjectRoots = () => argv.projectRoots;
+      }
+
+      server = await MetroApi.runServer({
+        ...argv,
+        config,
+      });
+
+      restarting = false;
+    }
+
+    const metroConfigLocation = await MetroApi.findMetroConfig(argv.config);
+
+    if (metroConfigLocation) {
+      await watchFile(metroConfigLocation, restart);
+    } else {
+      await restart();
+    }
+  }),
 });

packages/metro/src/index.js

@@ -22,6 +22,8 @@ const fs = require('fs');
 const getMaxWorkers = require('./lib/getMaxWorkers');
 const http = require('http');
 const https = require('https');
+const makeBuildCommand = require('./commands/build');
+const makeServeCommand = require('./commands/serve');
 const outputBundle = require('./shared/output/bundle');
 const path = require('path');
 
@@ -31,12 +33,13 @@ const {Terminal} = require('metro-core');
 
 import type {ConfigT} from './Config';
 import type {GlobalTransformCache} from './lib/GlobalTransformCache';
-import type {Options as ServerOptions} from './shared/types.flow';
+import type {TransformCache} from './lib/TransformCaching';
 import type {Reporter} from './lib/reporting';
 import type {RequestOptions, OutputOptions} from './shared/types.flow.js';
-import type {TransformCache} from './lib/TransformCaching';
+import type {Options as ServerOptions} from './shared/types.flow';
 import type {Server as HttpServer} from 'http';
 import type {Server as HttpsServer} from 'https';
+import typeof Yargs from 'yargs';
 
 export type {ConfigT} from './Config';
 
@@ -400,7 +403,7 @@ exports.findMetroConfig = function(
 
 exports.loadMetroConfig = function(
   filename: ?string,
-  // $FlowFixMe: This is a known Flow issue where it doesn't detect that an empty object is a valid value for a strict shape where all the members are optionals
+  // $FlowFixMe TODO T26072405
   searchOptions: MetroConfigSearchOptions = {},
 ): ConfigT {
   const location = exports.findMetroConfig(filename, searchOptions);
@@ -411,6 +414,32 @@ exports.loadMetroConfig = function(
   return config ? Config.normalize(config) : Config.DEFAULT;
 };
 
+type BuildCommandOptions = {||} | null;
+type ServeCommandOptions = {||} | null;
+
+exports.attachMetroCli = function(
+  yargs: Yargs,
+  {
+    // $FlowFixMe TODO T26072405
+    build = {},
+    // $FlowFixMe TODO T26072405
+    serve = {},
+  }: {
+    build: BuildCommandOptions,
+    serve: ServeCommandOptions,
+  } = {},
+) {
+  if (build) {
+    const {command, description, builder, handler} = makeBuildCommand();
+    yargs.command(command, description, builder, handler);
+  }
+  if (serve) {
+    const {command, description, builder, handler} = makeServeCommand();
+    yargs.command(command, description, builder, handler);
+  }
+  return yargs;
+};
+
 exports.Config = Config;
 exports.defaults = defaults;