Add relay-config package for centralised configuration

gulpfile.js

@@ -54,6 +54,7 @@ const babelOptions = require('./scripts/getBabelOptions')({
     'babel-plugin-macros': 'babel-plugin-macros',
     chalk: 'chalk',
     child_process: 'child_process',
+    cosmiconfig: 'cosmiconfig',
     crypto: 'crypto',
     'fast-glob': 'fast-glob',
     'fb-watchman': 'fb-watchman',
@@ -243,6 +244,21 @@ const builds = [
       },
     ],
   },
+  {
+    package: 'relay-config',
+    exports: {
+      index: 'index.js',
+    },
+    bundles: [
+      {
+        entry: 'index.js',
+        output: 'relay-config',
+        libraryName: 'RelayConfig',
+        target: 'node',
+        noMinify: true, // Note: uglify can't yet handle modern JS
+      },
+    ],
+  },
 ];
 
 function clean() {
@@ -260,6 +276,7 @@ const modules = gulp.parallel(
               '!**/__tests__/**',
               '!**/__flowtests__/**',
               '!**/__mocks__/**',
+              '!**/node_modules/**',
             ],
             {
               cwd: path.join(PACKAGES, build.package),

package.json

@@ -37,6 +37,7 @@
     "babel-plugin-tester": "^6.0.1",
     "babel-preset-fbjs": "^3.1.2",
     "chalk": "^2.4.1",
+    "cosmiconfig": "^5.2.1",
     "del": "3.0.0",
     "eslint": "5.4.0",
     "eslint-config-fbjs": "2.0.1",

packages/babel-plugin-relay/BabelPluginRelay.js

@@ -17,6 +17,12 @@ const getValidGraphQLTag = require('./getValidGraphQLTag');
 const getValidRelayQLTag = require('./getValidRelayQLTag');
 const invariant = require('./invariant');
 
+let RelayConfig;
+try {
+  // eslint-disable-next-line no-eval
+  RelayConfig = eval('require')('relay-config');
+} catch (_) {}
+
 import type {Validator} from './RelayQLTransformer';
 
 export type RelayPluginOptions = {
@@ -38,7 +44,7 @@ export type RelayPluginOptions = {
   snakeCase?: boolean,
   substituteVariables?: boolean,
   validator?: Validator<any>,
-  // Directory as specified by outputDir when running relay-compiler
+  // Directory as specified by artifactDirectory when running relay-compiler
   artifactDirectory?: string,
 };
 
@@ -115,7 +121,8 @@ module.exports = function BabelPluginRelay(context: {types: $FlowFixMe}): any {
   return {
     visitor: {
       Program(path, state) {
-        path.traverse(visitor, state);
+        const config = RelayConfig && RelayConfig.loadConfig();
+        path.traverse(visitor, {...state, opts: {...config, ...state.opts}});
       },
     },
   };

packages/relay-compiler/bin/RelayCompilerBin.js

@@ -15,96 +15,178 @@ require('@babel/polyfill');
 const {main} = require('./RelayCompilerMain');
 const yargs = require('yargs');
 
-// Collect args
+let RelayConfig;
+try {
+  // eslint-disable-next-line no-eval
+  RelayConfig = eval('require')('relay-config');
+} catch (_) {}
+
+import type {Config} from './RelayCompilerMain';
+
+type OptionBase<T> = {|
+  describe: string,
+  default?: T,
+|};
+
+/**
+ * Maps from a value type to a corresponding yargs option object type.
+ *
+ * For instance, a required array string type maps to:
+ *
+ *     { describe: string, default?: Array<string>, type: 'string', array: true, demandOption: true }
+ *
+ * Whereas an optional single string type maps to:
+ *
+ *     { describe: string, default?: string, type: 'string', array: false, demandOption: false }
+ */
+type OptionTypeMap<T> = $Call<
+  | ((
+      Array<string>,
+    ) => {|...OptionBase<Array<string>>, array: true, type: 'string'|})
+  | ((
+      ?string,
+    ) => {|
+      ...OptionBase<string>,
+      array: false,
+      demandOption: false,
+      type: 'string',
+    |})
+  | (string => {|
+      ...OptionBase<string>,
+      array: false,
+      demandOption: true,
+      type: 'string',
+    |})
+  | ((?boolean) => {|...OptionBase<boolean>, type: 'boolean'|})
+  | (({}) => {|...OptionBase<{}>, type: 'object'|}),
+  T,
+>;
+
+/**
+ * Generates an object type with all keys from Config and values mapped to yargs option object types.
+ */
+type Options = $ObjMap<
+  // TODO: Unsure how to remove function types from T with Flow, so instead just narrowing it here by hand.
+  Config & {language: string},
+  <T>(T) => OptionTypeMap<T>,
+>;
+
+const options: Options = {
+  schema: {
+    describe: 'Path to schema.graphql or schema.json',
+    demandOption: true,
+    type: 'string',
+    array: false,
+  },
+  src: {
+    describe: 'Root directory of application code',
+    demandOption: true,
+    type: 'string',
+    array: false,
+  },
+  include: {
+    describe: 'Directories to include under src',
+    type: 'string',
+    array: true,
+    default: ['**'],
+  },
+  exclude: {
+    describe: 'Directories to ignore under src',
+    type: 'string',
+    array: true,
+    default: ['**/node_modules/**', '**/__mocks__/**', '**/__generated__/**'],
+  },
+  extensions: {
+    array: true,
+    describe:
+      'File extensions to compile (defaults to extensions provided by the ' +
+      'language plugin)',
+    type: 'string',
+  },
+  verbose: {
+    describe: 'More verbose logging',
+    type: 'boolean',
+    default: false,
+  },
+  quiet: {
+    describe: 'No output to stdout',
+    type: 'boolean',
+    default: false,
+  },
+  watchman: {
+    describe: 'Use watchman when not in watch mode',
+    type: 'boolean',
+    default: true,
+  },
+  watch: {
+    describe: 'If specified, watches files and regenerates on changes',
+    type: 'boolean',
+    default: false,
+  },
+  validate: {
+    describe:
+      'Looks for pending changes and exits with non-zero code instead of ' +
+      'writing to disk',
+    type: 'boolean',
+    default: false,
+  },
+  persistOutput: {
+    describe:
+      'A path to a .json file where persisted query metadata should be saved',
+    demandOption: false,
+    type: 'string',
+    array: false,
+  },
+  noFutureProofEnums: {
+    describe:
+      'This option controls whether or not a catch-all entry is added to enum type definitions ' +
+      'for values that may be added in the future. Enabling this means you will have to update ' +
+      'your application whenever the GraphQL server schema adds new enum values to prevent it ' +
+      'from breaking.',
+    type: 'boolean',
+    default: false,
+  },
+  language: {
+    describe:
+      'The name of the language plugin used for input files and artifacts',
+    demandOption: false,
+    type: 'string',
+    array: false,
+    default: 'javascript',
+  },
+  artifactDirectory: {
+    describe:
+      'A specific directory to output all artifacts to. When enabling this ' +
+      'the babel plugin needs `artifactDirectory` set as well.',
+    demandOption: false,
+    type: 'string',
+    array: false,
+  },
+  customScalars: {
+    describe:
+      'Mappings from custom scalars in your schema to built-in GraphQL ' +
+      'types, for type emission purposes. (Uses yargs dot-notation, e.g. ' +
+      '--customScalars.URL=String)',
+    type: 'object',
+  },
+};
+
+// Load external config
+const config = RelayConfig && RelayConfig.loadConfig();
+
+// Parse CLI args
 const argv = yargs
   .usage(
     'Create Relay generated files\n\n' +
       '$0 --schema <path> --src <path> [--watch]',
   )
-  .options({
-    schema: {
-      describe: 'Path to schema.graphql or schema.json',
-      demandOption: true,
-      type: 'string',
-    },
-    src: {
-      describe: 'Root directory of application code',
-      demandOption: true,
-      type: 'string',
-    },
-    include: {
-      array: true,
-      default: ['**'],
-      describe: 'Directories to include under src',
-      type: 'string',
-    },
-    exclude: {
-      array: true,
-      default: ['**/node_modules/**', '**/__mocks__/**', '**/__generated__/**'],
-      describe: 'Directories to ignore under src',
-      type: 'string',
-    },
-    extensions: {
-      array: true,
-      describe:
-        'File extensions to compile (defaults to extensions provided by the ' +
-        'language plugin)',
-      type: 'string',
-    },
-    verbose: {
-      describe: 'More verbose logging',
-      type: 'boolean',
-    },
-    quiet: {
-      describe: 'No output to stdout',
-      type: 'boolean',
-    },
-    watchman: {
-      describe: 'Use watchman when not in watch mode',
-      type: 'boolean',
-      default: true,
-    },
-    watch: {
-      describe: 'If specified, watches files and regenerates on changes',
-      type: 'boolean',
-    },
-    validate: {
-      describe:
-        'Looks for pending changes and exits with non-zero code instead of ' +
-        'writing to disk',
-      type: 'boolean',
-      default: false,
-    },
-    'persist-output': {
-      describe:
-        'A path to a .json file where persisted query metadata should be saved',
-    },
-    noFutureProofEnums: {
-      describe:
-        'This option controls whether or not a catch-all entry is added to enum type definitions ' +
-        'for values that may be added in the future. Enabling this means you will have to update ' +
-        'your application whenever the GraphQL server schema adds new enum values to prevent it ' +
-        'from breaking.',
-      default: false,
-    },
-    language: {
-      describe:
-        'The name of the language plugin used for input files and artifacts',
-      type: 'string',
-      default: 'javascript',
-    },
-    artifactDirectory: {
-      describe:
-        'A specific directory to output all artifacts to. When enabling this ' +
-        'the babel plugin needs `artifactDirectory` set as well.',
-      type: 'string',
-      default: null,
-    },
-  })
+  .options(options)
+  // Apply externally loaded config through the yargs API so that we can leverage yargs' defaults and have them show up
+  // in the help banner.
+  .config(config)
   .help().argv;
 
-// Run script with args
-// $FlowFixMe: Invalid types for yargs. Please fix this when touching this code.
+// Start the application
 main(argv).catch(error => {
   console.error(String(error.stack || error));
   process.exit(1);