feat(sass): exports conditions (Anidetrix#197)

* feat: add basic support resolving conditional package exports

* resolve conflicts

* adjust naming

Co-authored-by: Anton Kudryavtsev <boblobl4@gmail.com>

src/loaders/sass/importer.ts

@@ -1,8 +1,9 @@
 import path from "path";
-import { resolveAsync, resolveSync } from "../../utils/resolve";
+import { packageFilterBuiler, resolveAsync, resolveSync } from "../../utils/resolve";
 import { getUrlOfPartial, isModule, normalizeUrl } from "../../utils/url";
 
 const extensions = [".scss", ".sass", ".css"];
+const conditions = ["sass", "style"];
 
 export const importer: sass.Importer = (url, importer, done): void => {
   const finalize = (id: string): void => done({ file: id.replace(/\.css$/i, "") });
@@ -11,7 +12,12 @@ export const importer: sass.Importer = (url, importer, done): void => {
   if (!isModule(url)) return next();
   const moduleUrl = normalizeUrl(url);
   const partialUrl = getUrlOfPartial(moduleUrl);
-  const options = { caller: "Sass importer", basedirs: [path.dirname(importer)], extensions };
+  const options = {
+    caller: "Sass importer",
+    basedirs: [path.dirname(importer)],
+    extensions,
+    packageFilter: packageFilterBuiler({ conditions }),
+  };
   // Give precedence to importing a partial
   resolveAsync([partialUrl, moduleUrl], options).then(finalize).catch(next);
 };
@@ -21,7 +27,12 @@ export const importerSync: sass.Importer = (url, importer): sass.Data => {
   if (!isModule(url)) return null;
   const moduleUrl = normalizeUrl(url);
   const partialUrl = getUrlOfPartial(moduleUrl);
-  const options = { caller: "Sass importer", basedirs: [path.dirname(importer)], extensions };
+  const options = {
+    caller: "Sass importer",
+    basedirs: [path.dirname(importer)],
+    extensions,
+    packageFilter: packageFilterBuiler({ conditions }),
+  };
   // Give precedence to importing a partial
   try {
     return finalize(resolveSync([partialUrl, moduleUrl], options));