# Chapter 4 - Why is the coordinator necessary?

**URL:** <https://forums.kodeco.com/t/chapter-4-why-is-the-coordinator-necessary/90190>\
**Category:** SwiftUI by Tutorials\
**Created:** [December 3, 2019, 11:17am UTC](https://forums.kodeco.com/t/chapter-4-why-is-the-coordinator-necessary/90190 "2019-12-03T11:17:33Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![maximilian](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/maximilian/32/110937_2.png) [@maximilian](https://forums.kodeco.com/u/maximilian)\
**Post date:** [December 3, 2019, 11:17am UTC](https://forums.kodeco.com/t/chapter-4-why-is-the-coordinator-necessary/90190/1 "2019-12-03T11:17:33Z")

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In chapter 4 we create a coordinator to sync the UISlider with the SwiftUI slider class, could we create a function in ColorUISlider that sets its value when the UISlider value changes instead of using a coordinator? or is there a reason that isn’t possible?

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**Author:** ![audrey](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/audrey/32/111607_2.png) [@audrey](https://forums.kodeco.com/u/audrey)\
**Post date:** [December 3, 2019, 12:01pm UTC](https://forums.kodeco.com/t/chapter-4-why-is-the-coordinator-necessary/90190/2 "2019-12-03T12:01:15Z")

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hi Maximilian! I think that’s a question to ask on the Apple forums 😉

there’s a whole lot of Combine going on below the surface, and this is how the WWDC session said it should work … it’s no different from Apple telling us to use view controllers or delegates or KVO.

if you find another way, let us know?