rescript-chokidar

ReScript bindings for chokidar

Installation

npm i rescript-chokidar

In your bsconfig.json add it to bs-dependencies

{
  ...,
  "bs-dependencies": [..., "rescript-chokidar"],
}

Examples

// One-liner for current directory
Chokidar.watch(".")->Chokidar.on(#all((. event, path, _) => Js.log2(event, path)))->ignore

// Example of a more typical implementation structure

// Initialize watcher.
let watcher = Chokidar.watch(
  ~options=Chokidar.options(
    ~ignored=[Anymatch.regex(%re("/(^|[\/\\])\../"))],
    ~persistent=true,
    (),
  ),
  "file, dir, glob, or array",
)

// Add event listeners.
watcher
->Chokidar.on(#add((. path, _) => Js.log(`File ${path} has been added`)))
->Chokidar.on(#change((. path, _) => Js.log(`File ${path} has been changed`)))
->Chokidar.on(#unlink((. path) => Js.log(`File ${path} has been removed`)))
->ignore

// More possible events.
watcher
->Chokidar.on(#addDir((. path, _) => Js.log(`Directory ${path} has been added`)))
->Chokidar.on(#unlinkDir((. path) => Js.log(`Directory ${path} has been removed`)))
->Chokidar.on(#error((. error) => Js.log(j`Watcher error: $error`)))
->Chokidar.on(#ready(() => Js.log("Initial scan complete. Ready for changes")))
->Chokidar.on(
  #raw(
    (event, path, details) => {
      // internal
      Js.log4("Raw event info:", event, path, details)
    },
  ),
)
->ignore

// 'add', 'addDir' and 'change' events also receive stat() results as second
// argument when available: https://nodejs.org/api/fs.html#fs_class_fs_stats
@get external size: Chokidar.stats => int = "size"
watcher
->Chokidar.on(
  #change(
    (. path, stats) =>
      switch stats {
      | None => ()
      | Some(val) => Js.log(`File ${path} changed size to ${val->size->Js.Int.toString}`)
      },
  ),
)
->ignore

// Watch new files.
watcher->Chokidar.add("new-file")->ignore
watcher->Chokidar.addMany(["new-file-2", "new-file-3", "**/other-file*"])->ignore

// Get list of actual paths being watched on the filesystem
let watchedPaths = watcher->Chokidar.getWatched

// Un-watch some files.
watcher->Chokidar.unwatch("new-file*")->ignore

// Stop watching.
// The method is async!
watcher->Chokidar.close->Js.Promise.then_(() => {
  Js.log("closed")
  Js.Promise.resolve()
}, _)->ignore

// Full list of options.
// Do not use this example!
Chokidar.watch(
  ~options=Chokidar.options(
    ~persistent=true,
    ~ignored=[Anymatch.glob("*.txt")],
    ~ignoreInitial=false,
    ~followSymlinks=true,
    ~cwd=".",
    ~disableGlobbing=false,
    ~usePolling=false,
    ~interval=100,
    ~binaryInterval=300,
    ~alwaysStat=false,
    ~depth=99,
    ~awaitWriteFinish=Chokidar.awaitWriteFinishCustom(
      ~stabilityThreshold=2000,
      ~pollInterval=100,
      (),
    ),
    ~ignorePermissionErrors=false,

    // or a custom 'atomicity delay' (Chokidar.atomicCustom), in milliseconds (default 100)
    ~atomic=Chokidar.atomicOn,
    (),
  ),
  "file",
)->ignore

Caveats

• A watcher extends EventEmmiter so it has more methods like removeAllListeners() etc. I didn't define them. If you need some of these methods, open an issue or a PR.

• Some listeners take an instance of fs.Stats as an argument. Unfortunately, there're no official bindings that would define it. Maybe they'll appear at some point, but in meantime it's defined as an abstract type Chokidar.stats. You can define your own accesors, or use a library like rescript-nodejs with a converter defined as external convertStats: Chokidar.stats => NodeJs.Fs.Stats.t = "%identity"