The DirsWatcher class is defined as a regular JavaScript class. In the recommended structure we show this:
const watcher = new DirsWatcher(name);
This makes watcher into an instance of this class. You can create as many DirsWatcher instances as your application requires, and each will execute independently.
The name parameter is simply the name of this instance, and is passed along with events so that your application can be certain of which DirsWatcher has sent the event.
The API of this object starts with the EventEmitter class. See: https://nodejs.org/api/events.html#events_class_eventemitter
The primary method, on('event-name', handler function), lets your application subscribe to the DirsWatcher events. All other EventEmitter methods are available.
The attribute dirs returns the configured directory stack.
The attribute name returns the name of the DirsWatcher instance.
Calling the watch method tells DirsWatcher the directory stack configuration to use, and begins the process of scanning for and reporting on files. If watch has already been called an error will be thrown. To call watch a second time, first call close then call watch.
The onChange, onAdd, onUnlink, and onReady methods handle sending the corresponding events. These methods are listening to the Chokidar instance, and interpret the data it provides into the vpinfo data structure described in Stacked Directory events
The getWatched method calls the Chokidar getWatched method and returns a list of files being watched.
The vpathForFSPath method computes the vpinfo object for a given filesystem path. It does not track down the stack entry in this object.
The stackForVPath method finds all files in the directory corresponding to the supplied virtual path.
The close method shuts down the Chokidar instance, the side effect being that this DirsWatcher instance will no longer be listening for events. To shut down a Node.js application, it is necessary to call this method for each DirsWatcher instance your application creates.
Your application may want to change the behavior, such as using a different data structure than the vpinfo object.
Your application can implement a custom instance like so:
class MyDirsWatcher extends DirsWatcher {
...
}
Then you go to town writing your own methods.