1 files changed, 45 insertions, 0 deletions
diff --git a/cli/rt/40_fs_events.js b/cli/rt/40_fs_events.js
new file mode 100644
index 000000000..ad1fd678f
--- /dev/null
+++ b/cli/rt/40_fs_events.js
@@ -0,0 +1,45 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
+((window) => {
+  const { sendSync, sendAsync } = window.__bootstrap.dispatchJson;
+  const { close } = window.__bootstrap.resources;
+
+  class FsWatcher {
+    #rid = 0;
+
+    constructor(paths, options) {
+      const { recursive } = options;
+      this.#rid = sendSync("op_fs_events_open", { recursive, paths });
+    }
+
+    get rid() {
+      return this.#rid;
+    }
+
+    next() {
+      return sendAsync("op_fs_events_poll", {
+        rid: this.rid,
+      });
+    }
+
+    return(value) {
+      close(this.rid);
+      return Promise.resolve({ value, done: true });
+    }
+
+    [Symbol.asyncIterator]() {
+      return this;
+    }
+  }
+
+  function watchFs(
+    paths,
+    options = { recursive: true },
+  ) {
+    return new FsWatcher(Array.isArray(paths) ? paths : [paths], options);
+  }
+
+  window.__bootstrap.fsEvents = {
+    watchFs,
+  };
+})(this);