feat: add support for home directory "~" in cd

Author: c4spar

src/runtime/cd.ts

@@ -8,7 +8,9 @@ export function cd(dir: string) {
     console.log($.brightBlue("$ %s"), `cd ${dir}`);
   }
   try {
-    if (dir[0] !== path.sep) {
+    if (dir[0] === "~") {
+      dir = path.join(homedir() as string, dir.slice(1));
+    } else if (dir[0] !== path.sep) {
       dir = new URL(dir, path.toFileUrl(cwd + path.sep)).pathname;
     }
     Deno.chdir(dir);
@@ -23,3 +25,15 @@ export function cd(dir: string) {
     error(err);
   }
 }
+
+function homedir(): string | null {
+  switch (Deno.build.os) {
+    case "windows":
+      return Deno.env.get("USERPROFILE") || null;
+    case "linux":
+    case "darwin":
+      return Deno.env.get("HOME") || null;
+    default:
+      throw Error("Failed to retrive home directory.");
+  }
+}