source: trip-planner-front/node_modules/watchpack/README.md@ 76712b2

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1# watchpack
2
3Wrapper library for directory and file watching.
4
5[![Build Status][build-status]][build-status-url]
6[![Build status][build-status-veyor]][build-status-veyor-url]
7[![Test coverage][coveralls-image]][coveralls-url]
8[![codecov][codecov]][codecov-url]
9[![downloads][downloads]][downloads-url]
10[![Github contributors][contributors]][contributors-url]
11
12## Concept
13
14watchpack high level API doesn't map directly to watchers. Instead a three level architecture ensures that for each directory only a single watcher exists.
15
16- The high level API requests `DirectoryWatchers` from a `WatcherManager`, which ensures that only a single `DirectoryWatcher` per directory is created.
17- A user-faced `Watcher` can be obtained from a `DirectoryWatcher` and provides a filtered view on the `DirectoryWatcher`.
18- Reference-counting is used on the `DirectoryWatcher` and `Watcher` to decide when to close them.
19- The real watchers are created by the `DirectoryWatcher`.
20- Files are never watched directly. This should keep the watcher count low.
21- Watching can be started in the past. This way watching can start after file reading.
22- Symlinks are not followed, instead the symlink is watched.
23
24## API
25
26```javascript
27var Watchpack = require("watchpack");
28
29var wp = new Watchpack({
30 // options:
31 aggregateTimeout: 1000,
32 // fire "aggregated" event when after a change for 1000ms no additional change occurred
33 // aggregated defaults to undefined, which doesn't fire an "aggregated" event
34
35 poll: true,
36 // poll: true - use polling with the default interval
37 // poll: 10000 - use polling with an interval of 10s
38 // poll defaults to undefined, which prefer native watching methods
39 // Note: enable polling when watching on a network path
40 // When WATCHPACK_POLLING environment variable is set it will override this option
41
42 followSymlinks: true,
43 // true: follows symlinks and watches symlinks and real files
44 // (This makes sense when symlinks has not been resolved yet, comes with a performance hit)
45 // false (default): watches only specified item they may be real files or symlinks
46 // (This makes sense when symlinks has already been resolved)
47
48 ignored: "**/.git"
49 // ignored: "string" - a glob pattern for files or folders that should not be watched
50 // ignored: ["string", "string"] - multiple glob patterns that should be ignored
51 // ignored: /regexp/ - a regular expression for files or folders that should not be watched
52 // All subdirectories are ignored too
53});
54
55// Watchpack.prototype.watch({
56// files: Iterable<string>,
57// directories: Iterable<string>,
58// missing: Iterable<string>,
59// startTime?: number
60// })
61wp.watch({
62 files: listOfFiles,
63 directories: listOfDirectories,
64 missing: listOfNotExistingItems,
65 startTime: Date.now() - 10000
66});
67// starts watching these files and directories
68// calling this again will override the files and directories
69// files: can be files or directories, for files: content and existence changes are tracked
70// for directories: only existence and timestamp changes are tracked
71// directories: only directories, directory content (and content of children, ...) and
72// existence changes are tracked.
73// assumed to exist, when directory is not found without further information a remove event is emitted
74// missing: can be files or directorees,
75// only existence changes are tracked
76// expected to not exist, no remove event is emitted when not found initially
77// files and directories are assumed to exist, when they are not found without further information a remove event is emitted
78// missing is assumed to not exist and no remove event is emitted
79
80wp.on("change", function(filePath, mtime, explanation) {
81 // filePath: the changed file
82 // mtime: last modified time for the changed file
83 // explanation: textual information how this change was detected
84});
85
86wp.on("remove", function(filePath, explanation) {
87 // filePath: the removed file or directory
88 // explanation: textual information how this change was detected
89});
90
91wp.on("aggregated", function(changes, removals) {
92 // changes: a Set of all changed files
93 // removals: a Set of all removed files
94 // watchpack gives up ownership on these Sets.
95});
96
97// Watchpack.prototype.pause()
98wp.pause();
99// stops emitting events, but keeps watchers open
100// next "watch" call can reuse the watchers
101// The watcher will keep aggregating events
102// which can be received with getAggregated()
103
104// Watchpack.prototype.close()
105wp.close();
106// stops emitting events and closes all watchers
107
108// Watchpack.prototype.getAggregated(): { changes: Set<string>, removals: Set<string> }
109const { changes, removals } = wp.getAggregated();
110// returns the current aggregated info and removes that from the watcher
111// The next aggregated event won't include that info and will only emitted
112// when futher changes happen
113// Can also be used when paused.
114
115// Watchpack.prototype.getTimeInfoEntries()
116var fileTimes = wp.getTimeInfoEntries();
117// returns a Map with all known time info objects for files and directories
118// this include info from files not directly watched
119// key: absolute path, value: object with { safeTime, timestamp }
120// safeTime: a point in time at which it is safe to say all changes happened before that
121// timestamp: only for files, the mtime timestamp of the file
122
123// (deprecated)
124// Watchpack.prototype.getTimes()
125var fileTimes = wp.getTimes();
126// returns an object with all known change times for files
127// this include timestamps from files not directly watched
128// key: absolute path, value: timestamp as number
129```
130
131[build-status]: https://travis-ci.org/webpack/watchpack.svg?branch=master
132[build-status-url]: https://travis-ci.org/webpack/watchpack
133[build-status-veyor]: https://ci.appveyor.com/api/projects/status/e5u2qvmugtv0r647/branch/master?svg=true
134[build-status-veyor-url]: https://ci.appveyor.com/project/sokra/watchpack/branch/master
135[coveralls-url]: https://coveralls.io/r/webpack/watchpack/
136[coveralls-image]: https://img.shields.io/coveralls/webpack/watchpack.svg
137[codecov]: https://codecov.io/gh/webpack/watchpack/branch/master/graph/badge.svg
138[codecov-url]: https://codecov.io/gh/webpack/watchpack
139[downloads]: https://img.shields.io/npm/dm/watchpack.svg
140[downloads-url]: https://www.npmjs.com/package/watchpack
141[contributors]: https://img.shields.io/github/contributors/webpack/watchpack.svg
142[contributors-url]: https://github.com/webpack/watchpack/graphs/contributors
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