1 files changed, 54 insertions, 0 deletions
diff --git a/runtime/js/40_fs_events.js b/runtime/js/40_fs_events.js
new file mode 100644
index 000000000..a179e8c1b
--- /dev/null
+++ b/runtime/js/40_fs_events.js
@@ -0,0 +1,54 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
+((window) => {
+  const core = window.Deno.core;
+  const { errors } = window.__bootstrap.errors;
+
+  class FsWatcher {
+    #rid = 0;
+
+    constructor(paths, options) {
+      const { recursive } = options;
+      this.#rid = core.jsonOpSync("op_fs_events_open", { recursive, paths });
+    }
+
+    get rid() {
+      return this.#rid;
+    }
+
+    async next() {
+      try {
+        return await core.jsonOpAsync("op_fs_events_poll", {
+          rid: this.rid,
+        });
+      } catch (error) {
+        if (error instanceof errors.BadResource) {
+          return { value: undefined, done: true };
+        } else if (error instanceof errors.Interrupted) {
+          return { value: undefined, done: true };
+        }
+        throw error;
+      }
+    }
+
+    return(value) {
+      core.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);