Visually Designing State

with Statecharts & React

Shawn McKay

Statecharts

1. why?

2. what?

3. woh!
4. how?

why statecharts?

 

"Are statecharts the next big UI paradigm?"
Luca Matteis (React Meetup Vancouver, Nov. 2017)

Designer: User Flow Diagram

Electronic Engineer: PLC Function Block Diagram

Embedded Engineer: Statecharts

JS Devs: Where's our visual design language?

Project Manager: UML State Diagram

Visual Design Tools

Plan A?

What percent of your time do you spend planning your frontend?

Plan ---------> Code

Make It Reliable

Deterministic

What can we learn from engineering?

Web developers have the luxury to be wreckless.

Constraints breed creativity. Limitations lead to better design.

Engineers don't focus on “which library?”, they

computer

Statecharts

1. Electronics offers a better paradigm for app development.

 

2. Focus on visually planning & designing systems

what?

1. What is state?

this.state = {}
this.setState(nextState)

State !== Data

State

Machine

2. State is finite

countable

States

1. Stopped

2. Playing

Trigger Events to Transition between States

3. Transitions are controlled

States

1. Stopped

2. Playing

3. Rewinding

4. FastForwarding

FastForward -!> Rewind

4. Guard Transitions

Stop -> Rewind, FastForward, Play

States

1. Stopped

2. Playing

3. Rewinding

4. FastForwarding

5. Eject

Title Text

Stop -> Eject

It starts to feel more like state is managing you. But why?

The ideal data structure for state is not a string, or an object.

5. State is a Graph

Graph

Graphs can be Visualized

Designed

AWS Step Functions

Walkman

Unfortunately, state graphs can be a ticking time bomb.

State Explosion

6. Statecharts

"A Visual Formalism For Complex Systems" (Harel, 1987)

State Types

Transitions, Events, Actions

Walkman

Statecharts can visually describe/design any deterministic system

BioCharts

WOH!

Statechart Tools

SCXML (W3C)

QT SCXML

Yakindu Statecharts

C++, Java, Typescript

What about                ?

We're late. It's early.

Sketch.Systems

XState Visualizer

The Goal

Prototyping

Sketch.Systems Demo

DevTools

Redux Devtools

XState Devtools (Experimental)

Live Statecharts

Testing

Deterministic UI
+
Snapshot Tests

Automated SnapShot Testing

Potentially Automate E2E Tests?

How?

XState

XState
Machine

Visualized State Machine

Xstate

stateless finite state machines and statecharts

Stateless

Stateful State Machine

React-Automata

Title Text

React-Automata

Stateful Component Patterns

1. State from Prop 

Not Recommended!

1. State from Prop

Not Recommended!

2. Render Prop with
Boolean Value Match

(ringing) is true/false
based on value pattern match
with state value

Title Text

Conditional Rendering

3. State from Context

3. State from Context

4. Action from Context

5. Action -> Component Method

5. Action -> Component Method

XStateful

React-Automata

XStateful

action -> component methods

action ->reducers

component state

instance state

Differences

actions with params

External State Machine

XStateful Machine

XStateful-React

Create XStateful Machine

XStateful-React

Title Text

Action -> Reducer,
Action -> Activity

Statecharts + Data

XStateful Extstate (data)

Conditional Render with  State & Data

Not recommended!

Render Prop State/Data/Update

Conclusion

Shawn McKay

shawn.j.mckay@gmail.com

Article: https://bit.ly/2OfVFqY

Visually Designing State

By Shawn McKay

Visually Designing State

A roadmap for developing applications with state machines & statecharts

  • 382
Loading comments...

More from Shawn McKay