handling-the-delete-event-on-watch.md

Handling the Delete Event on Watch

You can listen for 'unlink' events to fire on the watcher returned from gulp.watch. This gets fired when files are removed, so you can delete the file from your destination directory, using something like:

'use strict';

var del = require('del');
var path = require('path');
var gulp = require('gulp');
var header = require('gulp-header');
var footer = require('gulp-footer');

gulp.task('scripts', function() {
  return gulp.src('src/**/*.js', {base: 'src'})
    .pipe(header('(function () {\r\n\t\'use strict\'\r\n'))
    .pipe(footer('\r\n})();'))
    .pipe(gulp.dest('build'));
});

gulp.task('watch', function () {
  var watcher = gulp.watch('src/**/*.js', ['scripts']);

  watcher.on('unlink', function (filepath) {
    var filePathFromSrc = path.relative(path.resolve('src'), filepath);
    // Concatenating the 'build' absolute path used by gulp.dest in the scripts task
    var destFilePath = path.resolve('build', filePathFromSrc);
    del.sync(destFilePath);
  });
});