 Resources from Isaac Mann in 2024

Our applications have lots of states that they can be in.

We usually remember “Loading” and “Successful”. If we’re having a particularly good day, we’ll get “Error” handled as well.

But what about other states that our application can be in?

Things like “Haven’t requested yet” or “The request was successful but there isn’t any data for us to show”.

It’s frustrating to think you’re “done” and then an edge case shows up (and this cycle repeats at least one more time).

Fed up with forgetting to handle the edge cases that appear when developing UIs, Isaac Mann started looking for a solution.

The answer? State machines.

In this course, Isaac will teach you how to plan and visualize your application’s states and the transitions between them through the creation of a React & XState powered Star Wars quiz app.

Statecharts are a formalism for modeling stateful, reactive systems. This is useful for declaratively describing the behavior of your application, from the individual components to the overall application logic.

xstate

Construct Sturdy UIs with XState

I go through the steps of taking an initial mockup, writing html, css layout, css styles and javascript to make a fully functioning webpage.

If you like the content so far, tweet @MannIsaac so I'll be motivated to finish the series.

Bite-size video tutorials for badass web developers.

egghead

From Mockup to Webpage

Components are all about encapsulating decisions. The perfect component makes good decisions for you without making you think about it. Of course, no one knows what decisions you’re going to want. To make components reusable, we set reasonable defaults, then allow you to override them when you don’t like the decisions made for you.

This course covers three broad categories of decisions that can be encapsulated in a component: state, view, and logic. You’ll learn to move an Angular component from completely static to very configurable using a variety of techniques.

The course takes some of the most popular components in web development and applies them to Angular. You’ll learn to write components that are opinionated about their core purpose, but allow parent components to overwrite secondary concerns when pain points require a more complex pattern.

Angular is a development platform for creating applications using modern web standards. Angular includes a wealth of essential features such as mobile gestures, animations, filtering, routing, data binding, security, internationalization, and beautiful UI components. It's extremely modular, lightweight, and easy to learn.

angular

Advanced Angular Component Patterns

Create a simple presentational component in Angular that encapsulates static view and logic decisions, but allows the parent component to set state with Inputs and listen to state changes with Outputs.

Expose an Angular Component’s State to the Parent Component

Allow the user to control the view of the toggle component.   Break the toggle component up into multiple composable components that can be rearranged by the app developer.

Write Compound Components with Angular’s ContentChild

Allow more than one child component of the same type.  Allow child components to be placed within the views of other custom components

Communicate Between Components Using Angular Dependency Injection

Allow the base toggle to be a tag (&lt;toggle>) or attribute (&lt;div toggle>).  The &lt;toggle> component has become less opinionated about the view, but has now taken on some responsibilities managing state.  We’ll decouple the state management piece by moving it into the toggleProvider directive. The toggleProvider directive provides state for all the &lt;toggle-off>, &lt;toggle-on> and &lt;toggle-button> components inside it.

Refactor Angular Component State Logic into Directives

What if we want to use some of the state in the toggle component inside of the customized view we’re providing.  Content components don’t have an easy way of accomplishing that.  However, TemplateRefs were specifically designed for this purpose.  TemplateRefs serve the same function as React’s Render Prop pattern.

Override Component UI with an Angular TemplateRef

If we’re going to make our toggle accessible, we’ll need to apply certain aria attributes to the control that does the toggling.  Instead of making the parent component handle that, we can provide a toggler directive that automatically applies the needed attributes.  Content directives allow the user to tell the UI component where to make those modifications.

Modify User Provided UI with Angular Content Directives

We’re getting into Inception territory here.  The user may want to override part of how the UI component Content Directives are modifying their provided UI.  So, we’ll let them configure the content directives.  The functionality of Content Directives is comparable to React’s Prop Getter pattern.

Allow Users to Configure Angular Content Directives

A component author has no way of knowing which state changes a consumer will want to override, but state reducers handle this problem by allowing the parent component to override any state change.

Expose Angular Component Logic Using State Reducers

Thanks for checking out this course!

My goal is for you to be able to use the patterns described in this course to make your components more flexible and easy to use.  Many thanks to Kent C. Dodds for his Advanced React Component Patterns course which was a big inspiration for this course.

This course covers patterns that make a component's state, logic or ui configurable by a parent component.  The patterns include: Compound Components, Provider Components, TemplateRefs and State Reducers.

I hope you enjoy this course as much as I did making it.

Course Overview: Advanced Angular Component Patterns

React is one of the web’s most popular frameworks for building JavaScript applications. 

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Whether you’re a React newbie or you’re ready for advanced techniques, you can level-up with egghead. Explore our in-depth courses, lessons, and community resources to build more powerful applications and crack open your career.

react

Finite state machines force you to do some up front thinking and be explicit about the states and transitions that are valid for your program.  We’ll use the XState visualizer tool to create a state machine to manage an http request.

Handle http request state with XState

If a network call returns an empty list, that should be rendered differently than a list with elements in it.  We’ll create two substates of the http success state (withData and withoutData) and choose which substate to transition to based on the http response using an automatic transition and a guard.

Block a State Transition with a Guard

All of this code lives in one component so far, but our apps have multiple components.  We'll split the app into list components and a question component with each component having its own state machine.  Each component will update its own state machine when it receives an event from a different component.

Communicate between State Machines in Different Components

In order to make sure the user actually picked the answer they wanted, we’ll add a confirmation state to the state machine that gives them the option to submit their answer or go back and change it.  When they go back, we need the state machine to remember all the substates that were active in the previous state.  We’ll accomplish this using a history state.

Save Previous States with a History State

Activities are useful for anything that needs to be executed at the beginning and end of a state.  Like an animation that needs to stop or an observable that needs to be unsubscribed.  We'll add a completely spurious `Dark Side` mode for the quiz that makes all the ui elements float around the screen so that users have a more difficult time taking the quiz.  Leaving `Dark Side` mode should return all elements to their original locations.

Execute Code when Entering and Exiting States using Activities

HTML 5 is the structure of our web pages. It is the markup that represents the DOM (document object model).

html

I break down a design mockup into its semantic information and encode that information into html.  I also show how to use Emmet tab completion to help speed up the repetitive task of making large html files.

Create html from a design mockup using Emmet tab completion

The specification describes a CSS box model optimized for user interface design. In the flex layout model, the children of a flex container can be laid out in any direction, and can “flex” their sizes, either growing to fill unused space or shrinking to avoid overflowing the parent.

flexbox

CSS Grid and Flexbox are very useful tools for providing the overall layout of a page.  I take a specific design and create the high level layout using css grid and then arrange an individual section using flex box.

Layout a webpage using css grid and flexbox

Cascading Style Sheets bring order and beauty to our applications.

Most webpages are nothing but rectangles, but css can do circles too.  We use css transforms (specifically translate and rotate) to break out of the rectangle mode and create a page where elements are positioned along the edge of a circle.

Layout a circular design using css transforms

It can be tedious to create a paired success and failure event for each external action that a state machine triggers.  Instead xstate can integrate directly with a promise and respond to the resolve or reject status of the promise itself.

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Isaac Mann