Implement sass --embedded in pure JS mode

Author: ntkme

Diff for: lib/src/compiler-path.ts

@@ -53,8 +53,10 @@ export const compilerCommand = (() => {
         `sass-embedded-${platform}-${arch}/dart-sass/src/sass.snapshot`
       ),
     ];
-  } catch (ignored) {
-    // ignored
+  } catch (e) {
+    if (!(isErrnoException(e) && e.code === 'MODULE_NOT_FOUND')) {
+      throw e;
+    }
   }
 
   try {
@@ -70,10 +72,21 @@ export const compilerCommand = (() => {
     }
   }
 
+  try {
+    return [
+      process.execPath,
+      p.join(p.dirname(require.resolve('sass')), 'sass.js'),
+    ];
+  } catch (e: unknown) {
+    if (!(isErrnoException(e) && e.code === 'MODULE_NOT_FOUND')) {
+      throw e;
+    }
+  }
+
   throw new Error(
     "Embedded Dart Sass couldn't find the embedded compiler executable. " +
       'Please make sure the optional dependency ' +
-      `sass-embedded-${platform}-${arch} is installed in ` +
+      `sass-embedded-${platform}-${arch} or sass is installed in ` +
       'node_modules.'
   );
 })();