How to run some gulp task based on a conditional

Question

Suppose I have this in my gulpfile:

gulp.task('foo', ...);

gulp.task('bar', function () {
  if (something) {
    // how do I run task 'foo' here?
  }
});

Answer 1

Gulp v3

Use deprecated but still working gulp.run

gulp.task('foo', ...)    

gulp.task('bar', function () {
  if (something) {
    gulp.run('foo')
  }
})

Alternatively, use use any plugins that consume task names as arguments, like run-sequence for example (which you will probably need anyway for running tasks in a strict sequence). I call my tasks conditionally this way (Gulp v3):

gulp.task('bar', (callback) => {
  if (something) {
    runSequence('foo', callback)
  } else {
    runSequence('foo', 'anotherTask', callback)
  }
})

Gulp v4

Your gulpfile, that is, gulpfile.babel.js for now, would set Gulp tasks as exported functions so you would call them directly:

export function foo () {
  ...
}

export function bar () {
  if (something) {
    foo()
  }
}