pp-parachute/bundlers/asset_watcher.js

Airdrop JS Applications

var EventEmitter = require('events').EventEmitter;
var Chokidar = require('chokidar');
var Promise = require('bluebird');
var fastbind = require('../util/fastbind');
var inherits = require('util').inherits;
var instances = [];

var AssetWatcher = function () {
    instances.push(this);
    EventEmitter.call(this);
    this.watcher = null;
    this.files = [];
    this.readyResolve = null;
    this.isReady = false;
};

inherits(AssetWatcher, EventEmitter);

AssetWatcher.prototype.watch = function (watchPaths) {
    this.files = [];
    this.fileMap = {};
    this.ready = false;
    this.watcher && this.watcher.close();
    this.watcher = Chokidar.watch(watchPaths);
    this.watcher.on('ready', fastbind(this.onReady, this));
    this.watcher.on('add', fastbind(this.onAdd, this));
    this.watcher.on('unlink', fastbind(this.onRemove, this));
    this.watcher.on('change', fastbind(this.onChange, this));
    this.watcher.on('error', fastbind(this.onError, this));
    return new Promise(fastbind(function (resolve) {
        this.readyResolve = resolve;
    }, this));
};

AssetWatcher.prototype.isFileWatched = function(filePath) {
    return this.fileMap[filePath];
};

AssetWatcher.prototype.ensureFileIsWatched = function(filePath) {
    if(this.fileMap[filePath]) return;
    this.fileMap[filePath] = true;
    this.watcher.add(filePath);
};

AssetWatcher.prototype.onReady = function () {
    this.readyResolve(this.listFiles());
    this.emit('ready', this.listFiles());
    this.isReady = true;
};

AssetWatcher.prototype.onAdd = function (pathToFile) {
    this.files.push(pathToFile);
    this.fileMap[pathToFile] = true;
    if (this.isReady) {
        this.emit('fileAdded', pathToFile);
    }
};

AssetWatcher.prototype.onRemove = function (pathToFile) {
    this.emit('fileRemoved', pathToFile);
    var index = this.files.indexOf(pathToFile);
    index !== -1 && this.files.splice(pathToFile);
    this.fileMap[pathToFile] = false;
};

AssetWatcher.prototype.onChange = function (pathToFile) {
    this.emit('fileChanged', pathToFile);
};

AssetWatcher.prototype.onError = function (error) {
    this.emit('error', error);
};

AssetWatcher.prototype.listFiles = function () {
    return this.files.slice(0);
};

AssetWatcher.prototype.shutdown = function () {
    this.watcher && this.watcher.close();
};

process.on('SIGINT', function () {
    for (var i = 0; i < instances.length; i++) {
        instances[i].shutdown();
    }
});

process.on('exit', function() {
    for (var i = 0; i < instances.length; i++) {
        instances[i].shutdown();
    }
});

module.exports = AssetWatcher;