Make node:fs load lazily

src/js/internal/fs/FSWatcher-lazy.ts

@@ -0,0 +1,22 @@
+var FSWatcher;
+
+var load = () => {
+  FSWatcher = require("internal/fs/FSWatcher").FSWatcher;
+  load = () => {};
+  return FSWatcher;
+};
+
+export default {
+  FSWatcherPropertyDescriptor: {
+    enumerable: true,
+    get() {
+      load();
+      return FSWatcher;
+    },
+    set() {},
+  },
+  watch: function watch(...args) {
+    load();
+    return new FSWatcher(...args);
+  },
+};

src/js/internal/fs/FSWatcher.ts

@@ -0,0 +1,71 @@
+var watchNodeFS: typeof import("node:fs").watch;
+
+const EventEmitter = require("node:events");
+class FSWatcher extends EventEmitter {
+  #watcher;
+  #listener;
+  constructor(path, options, listener) {
+    super();
+
+    if (!watchNodeFS) {
+      const nodeFS = Bun.fs();
+      watchNodeFS = nodeFS.watch.bind(nodeFS) as any;
+    }
+
+    if (typeof options === "function") {
+      listener = options;
+      options = {};
+    } else if (typeof options === "string") {
+      options = { encoding: options };
+    }
+
+    if (typeof listener !== "function") {
+      listener = () => {};
+    }
+
+    this.#listener = listener;
+    try {
+      this.#watcher = watchNodeFS(path, options || {}, this.#onEvent.bind(this));
+    } catch (e) {
+      if (!e.message?.startsWith("FileNotFound")) {
+        throw e;
+      }
+      const notFound = new Error(`ENOENT: no such file or directory, watch '${path}'`);
+      notFound.code = "ENOENT";
+      notFound.errno = -2;
+      notFound.path = path;
+      notFound.syscall = "watch";
+      notFound.filename = path;
+      throw notFound;
+    }
+  }
+
+  #onEvent(eventType, filenameOrError) {
+    if (eventType === "error" || eventType === "close") {
+      this.emit(eventType, filenameOrError);
+    } else {
+      this.emit("change", eventType, filenameOrError);
+      this.#listener(eventType, filenameOrError);
+    }
+  }
+
+  close() {
+    this.#watcher?.close();
+    this.#watcher = null;
+  }
+
+  ref() {
+    this.#watcher?.ref();
+  }
+
+  unref() {
+    this.#watcher?.unref();
+  }
+
+  // https://github.com/nodejs/node/blob/9f51c55a47702dc6a0ca3569853dd7ba022bf7bb/lib/internal/fs/watchers.js#L259-L263
+  start() {}
+}
+
+export default {
+  FSWatcher,
+};

src/js/internal/fs/ReadStream-lazy.ts

@@ -0,0 +1,20 @@
+var ReadStream;
+function load() {
+  return require("internal/fs/ReadStream").ReadStream;
+}
+
+export default {
+  ReadStreamPropertyDescriptor: {
+    enumerable: true,
+
+    get() {
+      return (ReadStream ??= load());
+    },
+
+    set() {},
+  },
+
+  createReadStream(path, options) {
+    return new (ReadStream ??= load())(path, options);
+  },
+};