feat: validate config with jest-validate

packages/metro-config/package.json

@@ -14,9 +14,13 @@
   "license": "MIT",
   "dependencies": {
     "cosmiconfig": "^5.0.5",
+    "jest-validate": "^24.5.0",
     "metro": "0.53.1",
     "metro-cache": "0.53.1",
     "metro-core": "0.53.1",
-    "pretty-format": "24.0.0-alpha.6"
+    "pretty-format": "^24.5.0"
+  },
+  "devDependencies": {
+    "strip-ansi": "^4.0.0"
   }
 }

packages/metro-config/src/__tests__/__snapshots__/loadConfig-test.js.snap

@@ -5,7 +5,6 @@ Object {
   "cacheStores": Array [],
   "cacheVersion": "1.0",
   "maxWorkers": 2,
-  "metro": true,
   "projectRoot": "/",
   "reporter": null,
   "resetCache": false,
@@ -138,7 +137,6 @@ Object {
   "cacheStores": Array [],
   "cacheVersion": "1.0",
   "maxWorkers": 2,
-  "metro": true,
   "projectRoot": "/",
   "reporter": null,
   "resetCache": false,
@@ -265,3 +263,119 @@ Object {
   ],
 }
 `;
+
+exports[`loadConfig validates config for projectRoot 1`] = `
+"● Validation Error:
+
+  Option \\"projectRoot\\" must be of type:
+    string
+  but instead received:
+    array
+
+  Example:
+  {
+    \\"projectRoot\\": \\"/path/to/project\\"
+  }
+"
+`;
+
+exports[`loadConfig validates config for resolver 1`] = `
+"● Validation Error:
+
+  Option \\"resolver\\" must be of type:
+    object
+  but instead received:
+    string
+
+  Example:
+  {
+    \\"resolver\\": {
+      \\"allowPnp\\": true,
+      \\"assetExts\\": [
+        \\"bmp\\",
+        \\"gif\\",
+        \\"jpg\\",
+        \\"jpeg\\",
+        \\"png\\",
+        \\"psd\\",
+        \\"svg\\",
+        \\"webp\\",
+        \\"m4v\\",
+        \\"mov\\",
+        \\"mp4\\",
+        \\"mpeg\\",
+        \\"mpg\\",
+        \\"webm\\",
+        \\"aac\\",
+        \\"aiff\\",
+        \\"caf\\",
+        \\"m4a\\",
+        \\"mp3\\",
+        \\"wav\\",
+        \\"html\\",
+        \\"json\\",
+        \\"pdf\\",
+        \\"yaml\\",
+        \\"yml\\",
+        \\"otf\\",
+        \\"ttf\\",
+        \\"zip\\"
+      ],
+      \\"platforms\\": [
+        \\"ios\\",
+        \\"android\\",
+        \\"windows\\",
+        \\"web\\"
+      ],
+      \\"sourceExts\\": [
+        \\"js\\",
+        \\"json\\",
+        \\"ts\\",
+        \\"tsx\\"
+      ],
+      \\"providesModuleNodeModules\\": [
+        \\"react-native\\",
+        \\"react-native-windows\\"
+      ],
+      \\"resolverMainFields\\": [
+        \\"browser\\",
+        \\"main\\"
+      ],
+      \\"extraNodeModules\\": {},
+      \\"hasteImplModulePath\\": \\"./path\\",
+      \\"blacklistRE\\": {},
+      \\"useWatchman\\": true
+    }
+  }
+"
+`;
+
+exports[`loadConfig validates config for server 1`] = `
+"● Validation Error:
+
+  Option \\"server.useGlobalHotkey\\" must be of type:
+    boolean
+  but instead received:
+    string
+
+  Example:
+  {
+    \\"useGlobalHotkey\\": true
+  }
+"
+`;
+
+exports[`loadConfig validates config for transformer 1`] = `
+"● Validation Error:
+
+  Option \\"transformer.enableBabelRuntime\\" must be of type:
+    boolean
+  but instead received:
+    number
+
+  Example:
+  {
+    \\"enableBabelRuntime\\": true
+  }
+"
+`;

packages/metro-config/src/__tests__/loadConfig-test.js

@@ -17,6 +17,7 @@ const {loadConfig} = require('../loadConfig');
 const getDefaultConfig = require('../defaults');
 const cosmiconfig = require('cosmiconfig');
 const prettyFormat = require('pretty-format');
+const stripAnsi = require('strip-ansi');
 
 describe('loadConfig', () => {
   beforeEach(() => {
@@ -25,7 +26,6 @@ describe('loadConfig', () => {
 
   it('can load config objects', async () => {
     const config = {
-      metro: true,
       reporter: null,
       maxWorkers: 2,
       cacheStores: [],
@@ -63,7 +63,6 @@ describe('loadConfig', () => {
   it('can load the config with a path', async () => {
     const config = defaultConfig => ({
       ...defaultConfig,
-      metro: true,
       reporter: null,
       maxWorkers: 2,
       cacheStores: [],
@@ -91,4 +90,73 @@ describe('loadConfig', () => {
 
     expect(prettyFormat(result)).toEqual(prettyFormat(defaultConfig));
   });
+
+  it('validates config for resolver', async () => {
+    expect.assertions(1);
+    const config = defaultConfig => ({
+      ...defaultConfig,
+      resolver: 'test',
+    });
+
+    cosmiconfig.setResolvedConfig(config);
+
+    try {
+      await loadConfig({});
+    } catch (error) {
+      expect(stripAnsi(error.message)).toMatchSnapshot();
+    }
+  });
+
+  it('validates config for server', async () => {
+    expect.assertions(1);
+    const config = defaultConfig => ({
+      ...defaultConfig,
+      server: {
+        useGlobalHotkey: 'test',
+      },
+    });
+
+    cosmiconfig.setResolvedConfig(config);
+
+    try {
+      await loadConfig({});
+    } catch (error) {
+      expect(stripAnsi(error.message)).toMatchSnapshot();
+    }
+  });
+
+  it('validates config for projectRoot', async () => {
+    expect.assertions(1);
+    const config = defaultConfig => ({
+      ...defaultConfig,
+      projectRoot: ['test'],
+    });
+
+    cosmiconfig.setResolvedConfig(config);
+
+    try {
+      await loadConfig({});
+    } catch (error) {
+      expect(stripAnsi(error.message)).toMatchSnapshot();
+    }
+  });
+
+  it('validates config for transformer', async () => {
+    expect.assertions(1);
+    const config = defaultConfig => ({
+      ...defaultConfig,
+      transformer: {
+        ...defaultConfig.transformer,
+        enableBabelRuntime: 1,
+      },
+    });
+
+    cosmiconfig.setResolvedConfig(config);
+
+    try {
+      await loadConfig({});
+    } catch (error) {
+      expect(stripAnsi(error.message)).toMatchSnapshot();
+    }
+  });
 });

packages/metro-config/src/defaults/validConfig.js

@@ -0,0 +1,28 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ * @format
+ */
+'use strict';
+
+module.exports = async () => {
+  const defaultConfig = await require('./index')('/path/to/project');
+  const validConfig = {
+    ...defaultConfig,
+    resolver: {
+      ...defaultConfig.resolver,
+      resolveRequest: function CustomResolver() {},
+      hasteImplModulePath: './path',
+    },
+    transformer: {
+      ...defaultConfig.transformer,
+      getTransformOptions: function getTransformOptions() {},
+    },
+  };
+
+  return validConfig;
+};

packages/metro-config/src/loadConfig.js

@@ -11,7 +11,9 @@
 'use strict';
 
 const cosmiconfig = require('cosmiconfig');
+const {validate} = require('jest-validate');
 const getDefaultConfig = require('./defaults');
+const validConfig = require('./defaults/validConfig');
 
 const {dirname, resolve, join} = require('path');
 
@@ -231,8 +233,8 @@ function overrideConfigWithArguments(
  * @return {object}                         Configuration returned
  */
 async function loadConfig(
-  argv: YargArguments = {},
-  defaultConfigOverrides: InputConfigT = {},
+  argv?: YargArguments = {},
+  defaultConfigOverrides?: InputConfigT = {},
 ): Promise<ConfigT> {
   argv.config = overrideArgument(argv.config);
 
@@ -242,6 +244,11 @@ async function loadConfig(
     defaultConfigOverrides,
   );
 
+  validate(configuration, {
+    exampleConfig: await validConfig(),
+    recursiveBlacklist: ['reporter'],
+  });
+
   // Override the configuration with cli parameters
   const configWithArgs = overrideConfigWithArguments(configuration, argv);