Allow configuration object in projects array

CHANGELOG.md

@@ -11,6 +11,8 @@
   ([#5154](https://github.com/facebook/jest/pull/5154))
 * `[jest-jasmine2]` Support generator functions as specs.
   ([#5166](https://github.com/facebook/jest/pull/5166))
+* `[jest-config]` Allow configuration objects inside `projects` array
+  ([#5176](https://github.com/facebook/jest/pull/5176))
 
 ### Chore & Maintenance
 

integration_tests/__tests__/multi_project_runner.test.js

@@ -154,6 +154,31 @@ test('"No tests found" message for projects', () => {
   );
 });
 
+test('objects in project configuration', () => {
+  writeFiles(DIR, {
+    '__tests__/file1.test.js': `
+      test('foo', () => {});
+    `,
+    '__tests__/file2.test.js': `
+      test('foo', () => {});
+    `,
+    'jest.config.js': `module.exports = {
+      projects: [
+        { testMatch: ['<rootDir>/__tests__/file1.test.js$'] },
+        { testMatch: ['<rootDir>/__tests__/file2.test.js$'] },
+      ]
+    };`,
+    'package.json': '{}',
+  });
+
+  const {stdout, stderr} = runJest(DIR);
+  expect(stderr).toEqual('');
+  expect(stdout).toContain(
+    '  2 files checked across 2 projects. ' +
+      'Run with `--verbose` for more details.',
+  );
+});
+
 test('resolves projects and their <rootDir> properly', () => {
   writeFiles(DIR, {
     '.watchmanconfig': '',

packages/jest-cli/src/cli/index.js

@@ -199,7 +199,9 @@ const ensureNoDuplicateConfigs = (parsedConfigs, projects) => {
       });
       throw new Error(message);
     }
-    configPathSet.add(configPath);
+    if (configPath !== null) {
+      configPathSet.add(configPath);
+    }
   }
 };
 
@@ -225,9 +227,11 @@ const getConfigs = (
   let hasDeprecationWarnings;
   let configs: Array<ProjectConfig> = [];
   let projects = projectsFromCLIArgs;
+  let configPath: ?Path;
 
   if (projectsFromCLIArgs.length === 1) {
     const parsedConfig = readConfig(argv, projects[0]);
+    configPath = parsedConfig.configPath;
 
     if (parsedConfig.globalConfig.projects) {
       // If this was a single project, and its config has `projects`
@@ -246,7 +250,9 @@ const getConfigs = (
   }
 
   if (projects.length > 1) {
-    const parsedConfigs = projects.map(root => readConfig(argv, root, true));
+    const parsedConfigs = projects.map(root =>
+      readConfig(argv, root, true, configPath)
+    );
     ensureNoDuplicateConfigs(parsedConfigs, projects);
     configs = parsedConfigs.map(({projectConfig}) => projectConfig);
     if (!hasDeprecationWarnings) {

packages/jest-config/src/index.js

@@ -17,24 +17,34 @@ import readConfigFileAndSetRootDir from './read_config_file_and_set_root_dir';
 
 function readConfig(
   argv: Argv,
-  packageRoot: string,
+  packageRootOrConfig: Path | ProjectConfig,
   // Whether it needs to look into `--config` arg passed to CLI.
   // It only used to read initial config. If the initial config contains
   // `project` property, we don't want to read `--config` value and rather
   // read individual configs for every project.
   skipArgvConfigOption?: boolean,
+  parentConfigPath?: ?Path,
 ): {
   configPath: ?Path,
   globalConfig: GlobalConfig,
   hasDeprecationWarnings: boolean,
   projectConfig: ProjectConfig,
 } {
   let rawOptions;
-  let configPath;
+  let configPath = null;
 
-  // A JSON string was passed to `--config` argument and we can parse it
-  // and use as is.
-  if (isJSONString(argv.config)) {
+  if (typeof packageRootOrConfig !== 'string') {
+    if (parentConfigPath) {
+      rawOptions = packageRootOrConfig;
+      rawOptions.rootDir = parentConfigPath;
+    } else {
+      throw new Error(
+        'jest: Cannot use configuration as an object without a file path',
+      );
+    }
+  } else if (isJSONString(argv.config)) {
+    // A JSON string was passed to `--config` argument and we can parse it
+    // and use as is.
     let config;
     try {
       config = JSON.parse(argv.config);
@@ -45,7 +55,7 @@ function readConfig(
     }
 
     // NOTE: we might need to resolve this dir to an absolute path in the future
-    config.rootDir = config.rootDir || packageRoot;
+    config.rootDir = config.rootDir || packageRootOrConfig;
     rawOptions = config;
     // A string passed to `--config`, which is either a direct path to the config
     // or a path to directory containing `package.json` or `jest.conf.js`
@@ -54,7 +64,7 @@ function readConfig(
     rawOptions = readConfigFileAndSetRootDir(configPath);
   } else {
     // Otherwise just try to find config in the current rootDir.
-    configPath = resolveConfigPath(packageRoot, process.cwd());
+    configPath = resolveConfigPath(packageRootOrConfig, process.cwd());
     rawOptions = readConfigFileAndSetRootDir(configPath);
   }
 

packages/jest-config/src/normalize.js

@@ -437,7 +437,8 @@ export default function normalize(options: InitialOptions, argv: Argv) {
             // Project can be specified as globs. If a glob matches any files,
             // We expand it to these paths. If not, we keep the original path
             // for the future resolution.
-            const globMatches = glob.sync(project);
+            const globMatches =
+              typeof project === 'string' ? glob.sync(project) : [];
             return projects.concat(globMatches.length ? globMatches : project);
           }, []);
         break;