feat: util/path trimStartDir

Author: EqualMa

src/util/path.test.ts

@@ -0,0 +1,37 @@
+import { trimStartDir } from "./path";
+
+test("trimStartDir", () => {
+  const startDirVariants = [
+    "some-dir/",
+    "./some-dir/",
+    "some-dir",
+    "./some-dir",
+  ];
+  for (const p of ["some-dir/", "./some-dir/", "some-dir", "./some-dir"]) {
+    for (const startDir of startDirVariants) {
+      expect(trimStartDir(p, startDir)).toBe(".");
+    }
+  }
+
+  for (const p of ["some-dir/some-file", "./some-dir/some-file"]) {
+    for (const startDir of startDirVariants) {
+      expect(trimStartDir(p, startDir)).toBe("some-file");
+    }
+  }
+
+  for (const p of ["some-dir/some-dir/", "./some-dir/some-dir/"]) {
+    for (const startDir of startDirVariants) {
+      expect(trimStartDir(p, startDir)).toBe("some-dir");
+    }
+  }
+
+  for (const p of [
+    "../some-dir/some-file",
+    "unknown-dir/some-file",
+    "/some-abs-dir/some-file",
+  ]) {
+    for (const startDir of startDirVariants) {
+      expect(trimStartDir(p, startDir)).toBe(p);
+    }
+  }
+});

src/util/path.ts

@@ -3,3 +3,10 @@ import { posix as pp } from "path";
 export function joinPath(...paths: string[]): string {
   return pp.join(...paths);
 }
+
+export function trimStartDir(p: string, startDir: string): string {
+  const res = pp.relative(startDir, p);
+
+  if (res.startsWith("../")) return p;
+  else return res || ".";
+}