jupyterlab/packages/metapackage/watch-files.js

// Copyright (c) Jupyter Development Team.
// Distributed under the terms of the Modified BSD License.
var fs = require('fs-extra');
var path = require('path');
var watch = require('watch');


// Handle a change to a file.
function handleFile(filename) {
  var parts = filename.split(path.sep);
  parts[0] = '..';
  parts[2] = 'lib';
  var target = path.resolve(parts.join(path.sep));
  fs.copySync(filename, target);
}

// Watch the files in lib.
watch.createMonitor('lib', function (monitor) {
  monitor.on('created', function (f) {
    watch.createMonitor(f, function (submonitor) {
      submonitor.on('changed', handleFile);
    });
  });
  monitor.on('changed', handleFile);

  // Handle the initial files.
  require('./build');

  // eslint-disable-next-line no-console
  console.log('Watching the metapackage files...');
});