feat(std/node): Added os.type (#8591)

std/node/os.ts

@@ -190,9 +190,18 @@ export function totalmem(): number {
   return Deno.systemMemoryInfo().total;
 }
 
-/** Not yet implemented */
+/** Returns operating system type (i.e. 'Windows_NT', 'Linux', 'Darwin') */
 export function type(): string {
-  notImplemented(SEE_GITHUB_ISSUE);
+  switch (Deno.build.os) {
+    case "windows":
+      return "Windows_NT";
+    case "linux":
+      return "Linux";
+    case "darwin":
+      return "Darwin";
+    default:
+      throw Error("unreachable");
+  }
 }
 
 /** Not yet implemented */

std/node/os_test.ts

@@ -47,6 +47,13 @@ Deno.test({
   },
 });
 
+Deno.test({
+  name: "type is a string",
+  fn() {
+    assertEquals(typeof os.type(), "string");
+  },
+});
+
 Deno.test({
   name: "getPriority(): PID must be a 32 bit integer",
   fn() {
@@ -245,13 +252,6 @@ Deno.test({
       Error,
       "Not implemented",
     );
-    assertThrows(
-      () => {
-        os.type();
-      },
-      Error,
-      "Not implemented",
-    );
     assertThrows(
       () => {
         os.uptime();