Allow ESLint rules to override extensions and glob patterns

Author: novemberborn

eslint-plugin-helper.js

@@ -4,15 +4,34 @@ const normalizeExtensions = require('./lib/extensions');
 const {hasExtension, normalizeGlobs, classify} = require('./lib/globs');
 const loadConfig = require('./lib/load-config');
 
-const cache = new Map();
+const configCache = new Map();
+const helperCache = new Map();
 
-function load(projectDir) {
-	if (cache.has(projectDir)) {
-		return cache.get(projectDir);
+function load(projectDir, overrides) {
+	const cacheKey = `${JSON.stringify(overrides)}\n${projectDir}`;
+	if (helperCache.has(cacheKey)) {
+		return helperCache.get(cacheKey);
+	}
+
+	let conf;
+	let babelConfig;
+	if (configCache.has(projectDir)) {
+		({conf, babelConfig} = configCache.get(projectDir));
+	} else {
+		conf = loadConfig(projectDir);
+		babelConfig = babelPipeline.validate(conf.babel);
+		configCache.set(projectDir, {conf, babelConfig});
+	}
+
+	if (overrides) {
+		conf = {...conf, ...overrides};
+		if (overrides.extensions) {
+			// Ignore extensions from the Babel config. Assume all extensions are
+			// provided in the override.
+			babelConfig = null;
+		}
 	}
 
-	const conf = loadConfig(projectDir);
-	const babelConfig = babelPipeline.validate(conf.babel);
 	const extensions = normalizeExtensions(conf.extensions || [], babelConfig);
 	const globs = {cwd: projectDir, ...normalizeGlobs(conf.files, conf.helpers, conf.sources, extensions.all)};
 
@@ -30,7 +49,7 @@ function load(projectDir) {
 			return classify(`${importPath}.${globs.extensions[0]}`, globs);
 		}
 	});
-	cache.set(projectDir, helper);
+	helperCache.set(cacheKey, helper);
 	return helper;
 }
 

test/eslint-plugin-helper.js

@@ -5,11 +5,16 @@ const {test} = require('tap');
 const {load} = require('../eslint-plugin-helper');
 
 const projectDir = path.join(__dirname, 'fixture/eslint-plugin-helper');
+const overrideDir = path.join(__dirname, 'fixture/eslint-plugin-helper/for-overriding');
 
 test('caches loaded configuration', t => {
 	const expected = load(projectDir);
-	const actual = load(projectDir);
-	t.is(expected, actual);
+	t.is(expected, load(projectDir));
+
+	const withOverride = load(projectDir, {});
+	t.not(expected, withOverride);
+	t.is(withOverride, load(projectDir, {}));
+
 	t.end();
 });
 
@@ -43,6 +48,41 @@ test('classifies files according to the configuration', t => {
 	t.end();
 });
 
+test('classifies files according to configuration override', t => {
+	const helper = load(overrideDir, {
+		extensions: ['foo'],
+		files: ['tests/**/*'],
+		helpers: ['helpers/*'],
+		sources: ['source.*']
+	});
+	t.deepEqual(helper.classifyFile(path.join(overrideDir, 'tests/test.foo')), {
+		isHelper: false,
+		isSource: false,
+		isTest: true
+	});
+	t.deepEqual(helper.classifyFile(path.join(overrideDir, 'tests/_helper.foo')), {
+		isHelper: true,
+		isSource: false,
+		isTest: false
+	});
+	t.deepEqual(helper.classifyFile(path.join(overrideDir, 'helpers/helper.foo')), {
+		isHelper: true,
+		isSource: false,
+		isTest: false
+	});
+	t.deepEqual(helper.classifyFile(path.join(overrideDir, 'source.foo')), {
+		isHelper: false,
+		isSource: true,
+		isTest: false
+	});
+	t.deepEqual(helper.classifyFile(path.join(overrideDir, 'tests/test.js')), {
+		isHelper: false,
+		isSource: false,
+		isTest: false
+	});
+	t.end();
+});
+
 test('classifies imports with extension according to the configuration', t => {
 	const helper = load(projectDir);
 	t.deepEqual(helper.classifyImport(path.join(projectDir, 'tests/test.foo')), {
@@ -68,6 +108,36 @@ test('classifies imports with extension according to the configuration', t => {
 	t.end();
 });
 
+test('classifies imports with extension according to the override', t => {
+	const helper = load(overrideDir, {
+		extensions: ['foo'],
+		files: ['tests/**/*'],
+		helpers: ['helpers/*'],
+		sources: ['source.*']
+	});
+	t.deepEqual(helper.classifyImport(path.join(overrideDir, 'tests/test.foo')), {
+		isHelper: false,
+		isSource: false,
+		isTest: true
+	});
+	t.deepEqual(helper.classifyImport(path.join(overrideDir, 'tests/_helper.foo')), {
+		isHelper: true,
+		isSource: false,
+		isTest: false
+	});
+	t.deepEqual(helper.classifyImport(path.join(overrideDir, 'helpers/helper.foo')), {
+		isHelper: true,
+		isSource: false,
+		isTest: false
+	});
+	t.deepEqual(helper.classifyImport(path.join(overrideDir, 'source.foo')), {
+		isHelper: false,
+		isSource: true,
+		isTest: false
+	});
+	t.end();
+});
+
 test('classifies imports without extension according to the configuration', t => {
 	const helper = load(projectDir);
 	t.deepEqual(helper.classifyImport(path.join(projectDir, 'tests/test')), {
@@ -92,3 +162,33 @@ test('classifies imports without extension according to the configuration', t =>
 	});
 	t.end();
 });
+
+test('classifies imports without extension according to the override', t => {
+	const helper = load(overrideDir, {
+		extensions: ['foo'],
+		files: ['tests/**/*'],
+		helpers: ['helpers/*'],
+		sources: ['source.*']
+	});
+	t.deepEqual(helper.classifyImport(path.join(overrideDir, 'tests/test')), {
+		isHelper: false,
+		isSource: false,
+		isTest: true
+	});
+	t.deepEqual(helper.classifyImport(path.join(overrideDir, 'tests/_helper')), {
+		isHelper: true,
+		isSource: false,
+		isTest: false
+	});
+	t.deepEqual(helper.classifyImport(path.join(overrideDir, 'helpers/helper')), {
+		isHelper: true,
+		isSource: false,
+		isTest: false
+	});
+	t.deepEqual(helper.classifyImport(path.join(overrideDir, 'source')), {
+		isHelper: false,
+		isSource: true,
+		isTest: false
+	});
+	t.end();
+});

test/fixture/eslint-plugin-helper/ava.config.js

@@ -1,6 +1,6 @@
 export default {
 	babel: false,
+	extensions: ['foo'],
 	files: ['tests/**/*'],
-	helpers: ['helpers/*'],
-	extensions: ['foo']
+	helpers: ['helpers/*']
 };

test/fixture/eslint-plugin-helper/for-overriding/ava.config.js

@@ -0,0 +1,8 @@
+export default {
+	babel: {
+		extensions: ['bar']
+	},
+	files: ['build/tests/**/*'],
+	helpers: ['build/helpers/*'],
+	sources: ['src/**/*']
+};

test/fixture/eslint-plugin-helper/for-overriding/package.json

@@ -0,0 +1 @@
+{}