1 files changed, 89 insertions, 1 deletions
diff --git a/src/js/node/fs.js b/src/js/node/fs.js
index ab6816904..2c6b8cfbe 100644
--- a/src/js/node/fs.js
+++ b/src/js/node/fs.js
@@ -7,7 +7,6 @@ const Stream = require("node:stream");
 const { isArrayBufferView } = require("node:util/types");
 
 const constants = $processBindingConstants.fs;
-const { COPYFILE_EXCL } = constants;
 
 var fs = Bun.fs();
 class FSWatcher extends EventEmitter {
@@ -65,6 +64,45 @@ class FSWatcher extends EventEmitter {
   unref() {
     this.#watcher?.unref();
   }
+
+  // https://github.com/nodejs/node/blob/9f51c55a47702dc6a0ca3569853dd7ba022bf7bb/lib/internal/fs/watchers.js#L259-L263
+  start() {}
+}
+
+/** Implemented in `node_fs_stat_watcher.zig` */
+// interface StatWatcherHandle {
+//   ref();
+//   unref();
+//   close();
+// }
+
+class StatWatcher extends EventEmitter {
+  // _handle: StatWatcherHandle;
+
+  constructor(path, options) {
+    super();
+    this._handle = fs.watchFile(path, options, this.#onChange.bind(this));
+  }
+
+  #onChange(curr, prev) {
+    this.emit("change", curr, prev);
+  }
+
+  // https://github.com/nodejs/node/blob/9f51c55a47702dc6a0ca3569853dd7ba022bf7bb/lib/internal/fs/watchers.js#L259-L263
+  start() {}
+
+  stop() {
+    this._handle?.close();
+    this._handle = null;
+  }
+
+  ref() {
+    this._handle?.ref();
+  }
+
+  unref() {
+    this._handle?.unref();
+  }
 }
 
 var access = function access(...args) {
@@ -316,6 +354,54 @@ var access = function access(...args) {
     return new FSWatcher(path, options, listener);
   };
 
+// TODO: move this entire thing into native code.
+// the reason it's not done right now is because there isnt a great way to have multiple
+// listeners per StatWatcher with the current implementation in native code. the downside
+// of this means we need to do path validation in the js side of things
+const statWatchers = new Map();
+let _pathModule;
+function getValidatedPath(p) {
+  if (p instanceof URL) return Bun.fileURLToPath(p);
+  if (typeof p !== "string") throw new TypeError("Path must be a string or URL.");
+  return (_pathModule ??= require("node:path")).resolve(p);
+}
+function watchFile(filename, options, listener) {
+  filename = getValidatedPath(filename);
+
+  if (typeof options === "function") {
+    listener = options;
+    options = {};
+  }
+
+  if (typeof listener !== "function") {
+    throw new TypeError("listener must be a function");
+  }
+
+  var stat = statWatchers.get(filename);
+  if (!stat) {
+    stat = new StatWatcher(filename, options);
+    statWatchers.set(filename, stat);
+  }
+  stat.addListener("change", listener);
+  return stat;
+}
+function unwatchFile(filename, listener) {
+  filename = getValidatedPath(filename);
+
+  var stat = statWatchers.get(filename);
+  if (!stat) return;
+  if (listener) {
+    stat.removeListener("change", listener);
+    if (stat.listenerCount("change") !== 0) {
+      return;
+    }
+  } else {
+    stat.removeAllListeners("change");
+  }
+  stat.stop();
+  statWatchers.delete(filename);
+}
+
 function callbackify(fsFunction, args) {
   try {
     const result = fsFunction.apply(fs, args.slice(0, args.length - 1));
@@ -1200,9 +1286,11 @@ export default {
   truncateSync,
   unlink,
   unlinkSync,
+  unwatchFile,
   utimes,
   utimesSync,
   watch,
+  watchFile,
   write,
   writeFile,
   writeFileSync,