simple-tree-watcher
v0.3.0
Published
Watches the FileSystem for changes
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SimpleTreeWatcher
Watches a directory tree for changes
Hopefully it actually works unlike other watch libaries
Example:
const SimpleTreeWatcher = require('simple-tree-watcher');
var dir = process.argv[2];
console.log("watching: ", dir);
var watcher = new SimpleTreeWatcher(dir);
watcher.on('add', function(f, s) { show("add :", f, s ); });
watcher.on('create', function(f, s) { show("create:", f, s ); });
watcher.on('remove', function(f, s, s2) { show("remove:", f, s, s2); });
watcher.on('change', function(f, s) { show("change:", f, s ); });
function show(event, filepath, stat, oldStat) {
console.log(event, filepath, stat.isDirectory() ? "dir" : "file");
}
Docs
create an instance of SimpleTreeWatcher
and attach events.
new SimpleTreeWatcher(path, options)
SimpleTreeWatcher
is an EventEmitter
so it has the standard EventEmitter
api.
Events
'add'
Emitted for every entry when you first start. Passed filename and stat
'create'
Emitted when an file or folder is created. Passed filename and stat
'remove'
Emitted when a file is deleted. Passed filename and last stat
'change'
Emitted when a file is change. Passed the filename, current stat, previous stat
Options
filter
A function that is passed the path for every file and directory. It should return true
to keep the file or directory or false
to reject it. The path passed
is relative to the original path when SimpleTreeWatcher
was created.
Methods
close
Stops watching the tree. No more events will be sent.
Philosophy / Goals
My hope is there will be no surprises. You will never get a change
or remove
event for something that you didn't previously get an add
or create
event for.
I didn't feel like adding a globbing options is a good thing. It would just bloat the library. You can write your own filter in a 1-3 lines of code so it seemed best to let you pick your own filtering methods
Similarly some watch function have debouncing options etc. All of that can be layered over this level. No need to bloat/clutter/obfusticate this simple library.
Platform Issues
Each platform behaves slightly different. In my testing
OSX
Add a file get a create
event for the file
Windows
Add a file get a create
event for the file and a change
event for the parent folder
Also on Windows a watcher may hold a lock or temp lock on a folder.
I haven't tracked this down. In the tests I delete a subfolder
which internally I instantly get an 'EPERM'
error from the watcher
for that folder. I handle that case. But, at the end of the test
I delete all the test files. Those deletes failed unless I closed
the watcher.
Linux
Add a file get both create
event and a change
event for the file