A wrapper and enhancements for fs.watch.
npm install node-watchvarwatch=require('node-watch');watch('file_or_dir',{recursive: true},function(evt,name){console.log('%s changed.',name);});Now it's fast to watch deep directories on macOS and Windows, since the recursive option is natively supported except on Linux.
// watch the whole diskwatch('/',{recursive: true},console.log);- Some editors will generate temporary files which will cause the callback function to be triggered multiple times.
- The callback function will only be triggered once on watching a single file.
Missing an option to watch a directory recursively.- Recursive watch is not supported on Linux or in older versions of nodejs.
- Keep it simple, stupid.
The usage and options of node-watch are compatible with fs.watch.
persistent: Boolean(default true)recursive: Boolean(default false)encoding: String(default 'utf8')
Extra options
filter: RegExp | FunctionReturn that matches the filter expression.
// filter with regular expressionwatch('./',{filter: /\.json$/});// filter with custom functionwatch('./',{filter: f=>!/node_modules/.test(f)});
Each file and directory will be passed to the filter to determine whether it will then be passed to the callback function. Like
Array.filterdoes inJavaScript. There are three kinds of return values for filter function:true: Will be passed to callback.false: Will not be passed to callback.skip: Same withfalse, and skip to watch all its subdirectories.
On Linux, where the
recursiveoption is not natively supported, it is more efficient to skip ignored directories by returning theskipflag:watch('./',{recursive: true,filter(f,skip){// skip node_modulesif(/\/node_modules/.test(f))returnskip;// skip .git folderif(/\.git/.test(f))returnskip;// only watch for js filesreturn/\.js$/.test(f);}});
If you prefer glob patterns you can use minimatch or picomatch together with filter:
constpm=require('picomatch');letisMatch=pm('*.js');watch('./',{filter: f=>isMatch(f)});
delay: Number(in ms, default 200)Delay time of the callback function.
// log after 5 secondswatch('./',{delay: 5000},console.log);
The events provided by the callback function is either update or remove, which is less confusing to fs.watch's rename or change.
watch('./',function(evt,name){if(evt=='update'){// on create or modify}if(evt=='remove'){// on delete}});The watch function returns a fs.FSWatcher like object as the same as fs.watch (>= v0.4.0).
letwatcher=watch('./',{recursive: true});watcher.on('change',function(evt,name){// callback});watcher.on('error',function(err){// handle error});watcher.on('ready',function(){// the watcher is ready to respond to changes});// closewatcher.close();// is closed?watcher.isClosed().on.once.emit.close.listeners.setMaxListeners.getMaxListeners
.isCloseddetect if the watcher is closed.getWatchedPathsget all the watched paths
Windows, node < v4.2.5
- Failed to detect
removeevent - Failed to get deleted filename or directory name
MacOS, node 0.10.x
- Will emit double event if the directory name is of one single character.
watch(['file1','file2'],console.log);#!/usr/bin/env node
// https://github.com/nodejs/node-v0.x-archive/issues/3211require('epipebomb')();letwatcher=require('node-watch')(process.argv[2]||'./',{recursive: true},console.log);process.on('SIGINT',watcher.close);Monitoring chrome from disk:
$ watch / | grep -i chromeIf you get ENOSPC error, but you actually have free disk space - it means that your OS watcher limit is too low and you probably want to recursively watch a big tree of files.
Follow this description to increase the limit: https://confluence.jetbrains.com/display/IDEADEV/Inotify+Watches+Limit
Thanks goes to all wonderful people who have helped this project.
MIT
Copyright (c) 2012-2021 yuanchuan