feat(compile): Add support for web workers in standalone mode (#17657)

This commit adds support for spawning Web Workers in self-contained
binaries created with "deno compile" subcommand.

As long as module requested in "new Worker" constructor is part of the
eszip (by means of statically importing it beforehand, or using "--include"
flag), then the worker can be spawned.

4 files changed, 41 insertions, 0 deletions

diff --git a/cli/tests/testdata/compile/workers/basic.out b/cli/tests/testdata/compile/workers/basic.out
new file mode 100644
index 000000000..9cf9aa18f
--- /dev/null
+++ b/cli/tests/testdata/compile/workers/basic.out
@@ -0,0 +1,5 @@
+worker.js imported from main thread
+Starting worker
+Hello from worker!
+Received 42
+Closing
diff --git a/cli/tests/testdata/compile/workers/basic.ts b/cli/tests/testdata/compile/workers/basic.ts
new file mode 100644
index 000000000..8edf58de9
--- /dev/null
+++ b/cli/tests/testdata/compile/workers/basic.ts
@@ -0,0 +1,11 @@
+import "./worker.ts";
+
+console.log("Starting worker");
+const worker = new Worker(
+  new URL("./worker.ts", import.meta.url),
+  { type: "module" },
+);
+
+setTimeout(() => {
+  worker.postMessage(42);
+}, 500);
diff --git a/cli/tests/testdata/compile/workers/not_in_module_map.ts b/cli/tests/testdata/compile/workers/not_in_module_map.ts
new file mode 100644
index 000000000..b43f8cb1f
--- /dev/null
+++ b/cli/tests/testdata/compile/workers/not_in_module_map.ts
@@ -0,0 +1,11 @@
+// This time ./worker.ts is not in the module map, so the worker
+// initialization will fail unless worker.js is passed as a side module.
+
+const worker = new Worker(
+  new URL("./worker.ts", import.meta.url),
+  { type: "module" },
+);
+
+setTimeout(() => {
+  worker.postMessage(42);
+}, 500);
diff --git a/cli/tests/testdata/compile/workers/worker.ts b/cli/tests/testdata/compile/workers/worker.ts
new file mode 100644
index 000000000..a1c357ab1
--- /dev/null
+++ b/cli/tests/testdata/compile/workers/worker.ts
@@ -0,0 +1,14 @@
+/// <reference no-default-lib="true" />
+/// <reference lib="deno.worker" />
+
+if (import.meta.main) {
+  console.log("Hello from worker!");
+
+  addEventListener("message", (evt) => {
+    console.log(`Received ${evt.data}`);
+    console.log("Closing");
+    self.close();
+  });
+} else {
+  console.log("worker.js imported from main thread");
+}