fix(resolveAlias): handle aliases ending with trailing slash (#155)

Co-authored-by: Pooya Parsa <pooya@pi0.io>

src/utils.ts

@@ -42,9 +42,16 @@ export function normalizeAliases(_aliases: Record<string, string>) {
 export function resolveAlias(path: string, aliases: Record<string, string>) {
   const _path = normalizeWindowsPath(path);
   aliases = normalizeAliases(aliases);
-  for (const alias in aliases) {
-    if (_path.startsWith(alias) && pathSeparators.has(_path[alias.length])) {
-      return join(aliases[alias], _path.slice(alias.length));
+  for (const [alias, to] of Object.entries(aliases)) {
+    if (!_path.startsWith(alias)) {
+      continue;
+    }
+
+    // Strip trailing slash from alias for check
+    const _alias = hasTrailingSlash(alias) ? alias.slice(0, -1) : alias;
+
+    if (hasTrailingSlash(_path[_alias.length])) {
+      return join(to, _path.slice(alias.length));
     }
   }
   return _path;
@@ -61,3 +68,9 @@ export function filename(path: string) {
 function _compareAliases(a: string, b: string) {
   return b.split("/").length - a.split("/").length;
 }
+
+// Returns true if path ends with a slash or **is empty**
+function hasTrailingSlash(path = "/") {
+  const lastChar = path[path.length - 1];
+  return lastChar === "/" || lastChar === "\\";
+}

test/utils.spec.ts

@@ -9,6 +9,10 @@ describe("alias", () => {
     "@": "/root",
     bingpot: "@/bingpot/index.ts",
     test: "@bingpot/index.ts",
+    "~": "/root/index.js",
+    "~/": "/src",
+    "~win": "C:/root/index.js",
+    "~win/": "C:/src",
   };
   const aliases = normalizeAliases(_aliases);
 
@@ -20,6 +24,10 @@ describe("alias", () => {
         "@foo/bar/utils": "@foo/bar/dist/utils.mjs",
         "bingpot": "/root/bingpot/index.ts",
         "test": "@bingpot/index.ts",
+        "~": "/root/index.js",
+        "~/": "/src",
+        "~win": "C:/root/index.js",
+        "~win/": "C:/src",
       }
     `);
   });
@@ -43,6 +51,10 @@ describe("alias", () => {
       expect(resolveAlias("foo/bar.js", aliases)).toBe("foo/bar.js");
       expect(resolveAlias("./bar.js", aliases)).toBe("./bar.js");
     });
+    it("respect ending with /", () => {
+      expect(resolveAlias("~/foo/bar", aliases)).toBe("/src/foo/bar");
+      expect(resolveAlias("~win/foo/bar", aliases)).toBe("C:/src/foo/bar");
+    });
   });
 });