feat: allow overriding commands from react-native.config.js

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,