archived-nodemon/lib/monitor/watch.js

module.exports = watch;
var chokidar = require('chokidar');
var config = require('../config');
var path = require('path');
var utils = require('../utils');
var bus = utils.bus;
var match = require('./match');
var watchers = [];
var debouncedBus;

function watch() {
  if (watchers.length) {
    return;
  }

  var dirs = [].slice.call(config.dirs);

  dirs.forEach(function (dir) {
    var watcher = chokidar.watch(dir, {
      // ignore our files, but also ignore dotfiles
      ignored: [config.options.ignore.re, /[\/\\]\./],
      persistent: true,
    });

    watcher.on('change', filterAndRestart);
    watchers.push(watcher);
  });

  bus.on('reset', function () {
    watchers.forEach(function (watcher) {
      watcher.close();
    });
    watchers = [];
  });
}

function filterAndRestart(files) {
  if (!Array.isArray(files)) {
    files = [files];
  }
  if (files.length) {
    if (utils.isWindows) {
      // ensure the drive letter is in uppercase (c:\foo -> C:\foo)
      files = files.map(function (f) {
        return f[0].toUpperCase() + f.slice(1);
      });
    }

    var cwd = process.cwd();
    utils.log.detail('files triggering change check: ' + files.map(function (file) {
      return path.relative(cwd, file);
    }).join(', '));

    var matched = match(files, config.options.monitor, config.options.execOptions.ext);

    utils.log.detail('changes after filters (before/after): ' + [files.length, matched.result.length].join('/'));

    // reset the last check so we're only looking at recently modified files
    config.lastStarted = Date.now();

    if (matched.result.length) {
      if (config.options.delay > 0) {
        utils.log.detail('delaying restart for ' + config.options.delay + 'ms');
        if (debouncedBus === undefined) {
          debouncedBus = debounce(restartBus, config.options.delay);
        }
        debouncedBus(matched);
      } else {
        return restartBus(matched);
      }
    }
  }
}


function restartBus(matched) {
  utils.log.status('restarting due to changes...');
  matched.result.map(function (file) {
    utils.log.detail(path.relative(process.cwd(), file));
  });

  if (config.options.verbose) {
    utils.log._log('');
  }

  bus.emit('restart', matched.result);
}

function debounce(fn, delay) {
  var timer = null;
  return function () {
    var context = this, args = arguments;
    clearTimeout(timer);
    timer = setTimeout(function () {
      fn.apply(context, args);
    }, delay);
  };
}