refactor(multi-entry)!: virtualised & entryFileName (#520)

BREAKING CHANGES: Outputs a multi-entry file with different default name

Refactored multi-entry to use plugin-virtual for resolving/loading the
multiple entries into a single entry file. Some tidy-up and adding a new
option, entryFileName, to override the default entry filename.

packages/multi-entry/README.md

@@ -17,7 +17,7 @@ _Note: `default` exports cannot be combined and exported by this plugin. Only na
 
 ## Requirements
 
-This plugin requires an [LTS](https://github.com/nodejs/Release) Node version (v8.0.0+) and Rollup v1.20.0+.
+This plugin requires an [LTS](https://github.com/nodejs/Release) Node version (v8.3.0+) and Rollup v1.20.0+.
 
 ## Install
 
@@ -73,6 +73,13 @@ Default: `true`
 
 If `true`, instructs the plugin to export named exports to the bundle from all entries. If `false`, the plugin will not export any entry exports to the bundle. This can be useful when wanting to combine code from multiple entry files, but not necessarily to export each entry file's exports.
 
+### `entryFileName`
+
+Type: `String`<br>
+Default: `'multi-entry.js'`
+
+`entryFileName` changes the name of the generated entry file. By default, it will override `outputOptions.entryFileNames` to be `'multi-entry.js'`.
+
 ## Supported Input Types
 
 This plugin extends Rollup's `input` option to support multiple new value types, in addition to a `String` specifying a path to a file.

packages/multi-entry/package.json

@@ -48,6 +48,7 @@
     "rollup": "^1.20.0 || ^2.0.0"
   },
   "dependencies": {
+    "@rollup/plugin-virtual": "^2.0.3",
     "matched": "^5.0.0"
   },
   "devDependencies": {

packages/multi-entry/src/index.js

@@ -1,56 +1,77 @@
-/* eslint-disable consistent-return, no-param-reassign */
+/* eslint-disable no-param-reassign */
 
-import matched from 'matched';
+import virtual from '@rollup/plugin-virtual';
+import { promise as matched } from 'matched';
 
-const entry = '\0rollup:plugin-multi-entry:entry-point';
+const DEFAULT_OUTPUT = 'multi-entry.js';
+const AS_IMPORT = 'import';
+const AS_EXPORT = 'export * from';
 
-export default function multiEntry(conf) {
-  let include = [];
-  let exclude = [];
-  let exporter = (path) => `export * from ${JSON.stringify(path)};`;
+export default function multiEntry(conf = {}) {
+  const config = {
+    include: [],
+    exclude: [],
+    entryFileName: DEFAULT_OUTPUT,
+    exports: true,
+    ...conf
+  };
+
+  let prefix = config.exports === false ? AS_IMPORT : AS_EXPORT;
+  const exporter = (path) => `${prefix} ${JSON.stringify(path)}`;
 
-  function configure(config) {
-    if (typeof config === 'string') {
-      include = [config];
-    } else if (Array.isArray(config)) {
-      include = config;
+  const configure = (input) => {
+    if (typeof input === 'string') {
+      config.include = [input];
+    } else if (Array.isArray(input)) {
+      config.include = input;
     } else {
-      include = config.include || [];
-      exclude = config.exclude || [];
-      if (config.exports === false) {
-        exporter = (path) => `import ${JSON.stringify(path)};`;
+      const { include = [], exclude = [], entryFileName = DEFAULT_OUTPUT, exports } = input;
+      config.include = include;
+      config.exclude = exclude;
+      config.entryFileName = entryFileName;
+      if (exports === false) {
+        prefix = AS_IMPORT;
       }
     }
-  }
+  };
 
-  if (conf) {
-    configure(conf);
-  }
+  let virtualisedEntry;
 
   return {
+    name: 'multi-entry',
+
     options(options) {
-      if (options.input && options.input !== entry) {
+      if (options.input !== config.entryFileName) {
         configure(options.input);
       }
-      options.input = entry;
+      return {
+        ...options,
+        input: config.entryFileName
+      };
     },
 
-    resolveId(id) {
-      if (id === entry) {
-        return entry;
-      }
+    outputOptions(options) {
+      return {
+        ...options,
+        entryFileNames: config.entryFileName
+      };
+    },
+
+    buildStart(options) {
+      const patterns = config.include.concat(config.exclude.map((pattern) => `!${pattern}`));
+      const entries = patterns.length
+        ? matched(patterns, { realpath: true }).then((paths) => paths.map(exporter).join('\n'))
+        : Promise.resolve('');
+
+      virtualisedEntry = virtual({ [options.input]: entries });
+    },
+
+    resolveId(id, importer) {
+      return virtualisedEntry && virtualisedEntry.resolveId(id, importer);
     },
 
     load(id) {
-      if (id === entry) {
-        if (!include.length) {
-          return Promise.resolve('');
-        }
-        const patterns = include.concat(exclude.map((pattern) => `!${pattern}`));
-        return matched(patterns, { realpath: true }).then((paths) =>
-          paths.map(exporter).join('\n')
-        );
-      }
+      return virtualisedEntry && virtualisedEntry.load(id);
     }
   };
 }

packages/multi-entry/test/test.js

@@ -72,3 +72,12 @@ test('allows to prevent exporting', async (t) => {
   t.falsy(code.includes('zero'));
   t.falsy(code.includes('one'));
 });
+
+test('makes a bundle with entryFileName as the filename', async (t) => {
+  const bundle = await rollup({
+    input: 'test/fixtures/{0,1}.js',
+    plugins: [multiEntry({ entryFileName: 'testing.js' })]
+  });
+  const [result] = await getCode(bundle, { format: 'cjs' }, true);
+  t.is(result.fileName, 'testing.js');
+});