[Package Importer] Embedded Host (#260)

Co-authored-by: Jonny Gerig Meyer <[email protected]>

Author: jamesnw

lib/index.mjs

@@ -4,6 +4,7 @@ export const compile = sass.compile;
 export const compileAsync = sass.compileAsync;
 export const compileString = sass.compileString;
 export const compileStringAsync = sass.compileStringAsync;
+export const NodePackageImporter = sass.NodePackageImporter;
 export const AsyncCompiler = sass.AsyncCompiler;
 export const Compiler = sass.Compiler;
 export const initAsyncCompiler = sass.initAsyncCompiler;
@@ -65,6 +66,10 @@ export default {
     defaultExportDeprecation();
     return sass.compileStringAsync;
   },
+  get NodePackageImporter() {
+    defaultExportDeprecation();
+    return sass.NodePackageImporter;
+  },
   get initAsyncCompiler() {
     defaultExportDeprecation();
     return sass.initAsyncCompiler;

lib/index.ts

@@ -31,6 +31,7 @@ export {
   compileString,
   compileAsync,
   compileStringAsync,
+  NodePackageImporter,
 } from './src/compile';
 export {initAsyncCompiler, AsyncCompiler} from './src/compiler/async';
 export {initCompiler, Compiler} from './src/compiler/sync';

lib/src/compile.ts

@@ -7,6 +7,8 @@ import {OptionsWithLegacy, StringOptionsWithLegacy} from './compiler/utils';
 import {initCompiler} from './compiler/sync';
 import {CompileResult} from './vendor/sass';
 
+export {NodePackageImporter} from './importer-registry';
+
 export function compile(
   path: string,
   options?: OptionsWithLegacy<'sync'>

lib/src/importer-registry.ts

@@ -11,6 +11,28 @@ import {FileImporter, Importer, Options} from './vendor/sass';
 import * as proto from './vendor/embedded_sass_pb';
 import {catchOr, thenOr, PromiseOr} from './utils';
 
+const entryPointDirectoryKey = Symbol();
+
+export class NodePackageImporter {
+  readonly [entryPointDirectoryKey]: string;
+
+  constructor(entryPointDirectory?: string) {
+    entryPointDirectory = entryPointDirectory
+      ? p.resolve(entryPointDirectory)
+      : require.main?.filename
+      ? p.dirname(require.main.filename)
+      : undefined;
+    if (!entryPointDirectory) {
+      throw new Error(
+        'The Node package importer cannot determine an entry point ' +
+          'because `require.main.filename` is not defined. ' +
+          'Please provide an `entryPointDirectory` to the `NodePackageImporter`.'
+      );
+    }
+    this[entryPointDirectoryKey] = entryPointDirectory;
+  }
+}
+
 /**
  * A registry of importers defined in the host that can be invoked by the
  * compiler.
@@ -30,7 +52,11 @@ export class ImporterRegistry<sync extends 'sync' | 'async'> {
 
   constructor(options?: Options<sync>) {
     this.importers = (options?.importers ?? [])
-      .map(importer => this.register(importer))
+      .map(importer =>
+        this.register(
+          importer as Importer<sync> | FileImporter<sync> | NodePackageImporter
+        )
+      )
       .concat(
         (options?.loadPaths ?? []).map(
           path =>
@@ -43,10 +69,17 @@ export class ImporterRegistry<sync extends 'sync' | 'async'> {
 
   /** Converts an importer to a proto without adding it to `this.importers`. */
   register(
-    importer: Importer<sync> | FileImporter<sync>
+    importer: Importer<sync> | FileImporter<sync> | NodePackageImporter
   ): proto.InboundMessage_CompileRequest_Importer {
     const message = new proto.InboundMessage_CompileRequest_Importer();
-    if ('canonicalize' in importer) {
+    if (importer instanceof NodePackageImporter) {
+      const importerMessage = new proto.NodePackageImporter();
+      importerMessage.entryPointDirectory = importer[entryPointDirectoryKey];
+      message.importer = {
+        case: 'nodePackageImporter',
+        value: importerMessage,
+      };
+    } else if ('canonicalize' in importer) {
       if ('findFileUrl' in importer) {
         throw new Error(
           'Importer may not contain both canonicalize() and findFileUrl(): ' +

lib/src/legacy/index.ts

@@ -5,6 +5,7 @@
 import * as fs from 'fs';
 import * as p from 'path';
 import {pathToFileURL, URL} from 'url';
+import {NodePackageImporter} from '../importer-registry';
 
 import {Exception} from '../exception';
 import {
@@ -31,6 +32,8 @@ import {
   LegacyStringOptions,
   Options,
   StringOptions,
+  Importer,
+  FileImporter,
 } from '../vendor/sass';
 import {wrapFunction} from './value/wrap';
 import {endOfLoadProtocol, LegacyImporterWrapper} from './importer';
@@ -158,7 +161,10 @@ function convertOptions<sync extends 'sync' | 'async'>(
 
   return {
     functions,
-    importers,
+    importers:
+      options.pkgImporter instanceof NodePackageImporter
+        ? [options.pkgImporter, ...(importers ?? [])]
+        : importers,
     sourceMap: wasSourceMapRequested(options),
     sourceMapIncludeSources: options.sourceMapContents,
     loadPaths: importers ? undefined : options.includePaths,
@@ -178,14 +184,20 @@ function convertStringOptions<sync extends 'sync' | 'async'>(
 ): StringOptions<sync> & {legacy: true} {
   const modernOptions = convertOptions(options, sync);
 
+  // Find the first non-NodePackageImporter to pass as legacy `importer` option.
+  // NodePackageImporter will be passed in `modernOptions.importers`.
+  const importer = modernOptions.importers?.find(
+    _importer => !(_importer instanceof NodePackageImporter)
+  ) as Importer<sync> | FileImporter<sync>;
+
   return {
     ...modernOptions,
     url: options.file
       ? options.importer
         ? pathToLegacyFileUrl(options.file)
         : pathToFileURL(options.file)
       : new URL(legacyImporterProtocol),
-    importer: modernOptions.importers ? modernOptions.importers[0] : undefined,
+    importer,
     syntax: options.indentedSyntax ? 'indented' : 'scss',
   };
 }

package.json

@@ -1,7 +1,7 @@
 {
   "name": "sass-embedded",
   "version": "1.70.0",
-  "protocol-version": "2.4.0",
+  "protocol-version": "2.5.0",
   "compiler-version": "1.70.0",
   "description": "Node.js library that communicates with Embedded Dart Sass using the Embedded Sass protocol",
   "repository": "sass/embedded-host-node",