feat: allow overriding commands from react-native.config.js (#2229)

* feat: allow overriding commands

* chore: remove duplicates

* chore: update snaphosts

* docs: add note about overriding config

Author: szymonrybczak

docs/plugins.md

@@ -27,6 +27,8 @@ At the startup, React Native CLI reads configuration from all dependencies liste
 
 At the end, an array of commands concatenated from all plugins is passed on to the CLI to be loaded after built-in commands.
 
+Also, you can provide your own configuration by creating a `react-native.config.js` file in the root of the project, which overrides the configuration from plugins.
+
 > See [`healthChecks`](./healthChecks.md) for information on how plugins can provide additional health checks for `npx react-native doctor`.
 
 ## Command interface

packages/cli-config/src/__tests__/__snapshots__/index-test.ts.snap

@@ -1,5 +1,18 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`command specified in root config should overwrite command in "react-native-foo" and "react-native-bar" packages 1`] = `
+Object {
+  "func": [Function],
+  "name": "foo-command",
+  "options": Array [
+    Object {
+      "description": "Custom option",
+      "name": "--option",
+    },
+  ],
+}
+`;
+
 exports[`should apply build types from dependency config 1`] = `
 Object {
   "name": "react-native-test",
@@ -35,11 +48,17 @@ exports[`should load commands from "react-native-foo" and "react-native-bar" pac
 Array [
   Object {
     "func": [Function],
-    "name": "foo-command",
+    "name": "bar-command",
   },
   Object {
     "func": [Function],
-    "name": "bar-command",
+    "name": "foo-command",
+    "options": Array [
+      Object {
+        "description": "Custom option",
+        "name": "--option",
+      },
+    ],
   },
 ]
 `;

packages/cli-config/src/__tests__/index-test.ts

@@ -128,6 +128,59 @@ test('should read a config of a dependency and use it to load other settings', (
   ).toMatchSnapshot();
 });
 
+test('command specified in root config should overwrite command in "react-native-foo" and "react-native-bar" packages', () => {
+  DIR = getTempDirectory('config_test_packages');
+  writeFiles(DIR, {
+    'node_modules/react-native-foo/package.json': '{}',
+    'node_modules/react-native-foo/react-native.config.js': `module.exports = {
+      commands: [
+        {
+          name: 'foo-command',
+          func: () => console.log('foo')
+        }
+      ]
+    }`,
+    'node_modules/react-native-bar/package.json': '{}',
+    'node_modules/react-native-bar/react-native.config.js': `module.exports = {
+      commands: [
+        {
+          name: 'bar-command',
+          func: () => console.log('bar')
+        }
+      ]
+    }`,
+    'package.json': `{
+      "dependencies": {
+        "react-native-foo": "0.0.1",
+        "react-native-bar": "0.0.1"
+      }
+    }`,
+    'react-native.config.js': `module.exports = {
+      reactNativePath: '.',
+      commands: [
+        {
+          name: 'foo-command',
+          func: () => {
+            console.log('overridden foo command');
+          },
+          options: [
+            {
+              name: '--option',
+              description: 'Custom option',
+            },
+          ],
+        },
+      ],
+    };`,
+  });
+  const {commands} = loadConfig(DIR);
+  const commandsNames = commands.map(({name}) => name);
+  const commandIndex = commandsNames.indexOf('foo-command');
+
+  expect(commands[commandIndex].options).not.toBeNull();
+  expect(commands[commandIndex]).toMatchSnapshot();
+});
+
 test('should merge project configuration with default values', () => {
   DIR = getTempDirectory('config_test_merge');
   writeFiles(DIR, {

packages/cli-config/src/loadConfig.ts

@@ -5,6 +5,7 @@ import {
   DependencyConfig,
   UserConfig,
   Config,
+  Command,
 } from '@react-native-community/cli-types';
 import {
   findProjectRoot,
@@ -72,6 +73,16 @@ function getReactNativeVersion(reactNativePath: string) {
   return 'unknown';
 }
 
+const removeDuplicateCommands = <T extends boolean>(commands: Command<T>[]) => {
+  const uniqueCommandsMap = new Map();
+
+  commands.forEach((command) => {
+    uniqueCommandsMap.set(command.name, command);
+  });
+
+  return Array.from(uniqueCommandsMap.values());
+};
+
 /**
  * Loads CLI configuration
  */
@@ -143,7 +154,10 @@ function loadConfig(projectRoot: string = findProjectRoot()): Config {
             );
           },
         }),
-        commands: [...acc.commands, ...config.commands],
+        commands: removeDuplicateCommands([
+          ...config.commands,
+          ...acc.commands,
+        ]),
         platforms: {
           ...acc.platforms,
           ...config.platforms,