Course Introduction

Environment Setup With nvm

Scaffolding a React Hook Library with npm init

Building a Skeleton create-react-app to Test the Hook

Building Title Looping Functionality with the useEffect Hook

Packaging react-use-please-stay as an npm Module using Rollup

Cleaning Up and Refactoring react-use-please-stay

In this module, you'll focus on scaffolding all the tooling, building, and an example app to test your hook.

Building the First Functionalities of the react-use-please-stay Hook

Implementing a Cascading Letter Functionality

Implementing a Marquee Functionality

Implementing Favicon Modification Functionality

Add Interval Time as a Hook Parameter

Add Should Always Play as a Hook Parameter

In this module, you'll build more complex functionalities like changing the document title in advanced ways and even altering the favicon.

Adding Advanced Functionalities to react-use-please-stay

Use Custom Types to Type the Hook Parameters

Adding a Development-only Warning Logger

Prevent Concurrent Usages of the Hook

Restore Original Values on Refocus and Unmount

Publish the Hook to npm

In this module, you'll go through some optimizations and improvements to make a truly state-of-the-art React Hook package, and publish it to npm.

Finishing Touches and Optimizations

Prepare the Example App as a Public Example Page

Publish the Example App to GitHub Pages

In this module, you'll publish the example app to double as a live example of the hook running, as well as a complete documentation site.

Finalizing and Publishing the Example App

In **Master Custom React Hooks with TypeScript**, you will learn everything you need to start — completely from scratch — to publishing a fully-fledged React Hook built with Typescript, including a variety of complex features, detailed documentation, and a fully interactive example site. The course spans **4 modules** with a total of **19 lessons** and **over 2 hours of video content**. Here's a preview of what you'll learn in each module:

After completing Craft a Custom React Hook npm Package with React and TypeScript, students now possess the skills to build amazing React Hooks with React and TypeScript.

What the Students are Saying

react

typescript

Organize and abstract away complexity with React Hooks.

19 Video Lessons on React and TypeScript

Interactive, Live Project Demos

Complete Project Source Code

### Master the Art of Building Advanced React Hooks with TypeScript

Welcome to "Master Custom React Hooks with TypeScript," a comprehensive online course designed to elevate your skills in React development, more preciesly in creating Custom React Hooks with TypeScript. Led by seasoned software engineer Chris Frewin, this course dives into the intricacies of building custom and open-source React Hooks using TypeScript.

### Why React Hooks are Such a Pain to Learn

Learning React Hooks can be a formidable journey, especially for seasoned engineers venturing into new territories. Add TypeScript to the mix and the challenge becomes even greater. Here are common challenges you may have encountered:

- The official React documentation is infamous for its lack of complex examples, and it's even harder to find production-ready examples using both React and TypeScript combined. 
- The intricacies of React Hooks and TypeScript may seem daunting, leading to a sense of overwhelm as you navigate through the complexities of these technologies.
- Integrating TypeScript seamlessly with React and understanding how to leverage it effectively can be a puzzle, causing frustration for those aiming to build robust applications.
- Mastering state management with React Hooks requires a deep understanding of React fundamentals. Many face challenges in effectively utilizing useState, useEffect, and other hooks for optimal application performance. One of these most famous pitfalls is the infinite re-render loop that can occur when using useEffect.

### How This Course Helps

This course addresses these frustrations head-on, providing you with practical lessons filled with code implementations based on real-world experience to navigate the complexities of React Hooks and TypeScript with confidence.

### Why Invest Your Time in React Hooks and TypeScript Now?

In the dynamic landscape of software development, staying current is crucial. Here's why learning React Hooks and TypeScript is not just beneficial but essential for software engineers like yourself:

1. **React with React Hooks and TypeScript reigns as the Gold Standard of Web Development:** Even today, React is still oen of the most popular JavaScript frontend framework. By mastering React Hooks and TypeScript, you position yourself at the forefront of modern web development, ensuring your skill set aligns with the latest industry standards.

2. **Enhanced Developer Productivity:** TypeScript's static typing and React's declarative approach can significantly boost your productivity, allowing you to catch errors early and streamline your development workflow.

3. **Industry Demand:** Employers increasingly seek developers well-versed in React Hooks and TypeScript. Adding these skills to your arsenal makes you a sought-after professional in today's competitive job market.

4. **Optimized Application Performance:** React Hooks provide a more efficient and scalable way to manage state and side effects, contributing to the creation of high-performance applications that meet user expectations.

5. **Community Support and Resources:** The React and TypeScript communities are thriving. Learning these technologies now means tapping into a vast pool of resources, support forums, and collaborative opportunities.

Investing your time in mastering React Hooks and TypeScript not only equips you with cutting-edge skills but also positions you for success in the ever-evolving field of software development allowing you to join the ranks of forward-thinking developers embracing these technologies.

### Course Content Overview
Course Overview: Total Modules: **4** Total Lessons: **19** Total Video Runtime: **2 hours, 19 minutes**

Build Powerful React Hooks with TypeScript

Learn how to build an advanced React Hook with TypeScript, you will start from a blank editor and end with a complete and published open-source npm package.
This course contains 19 lessons, each complete with live coding examples for students to study and build upon. 
By the end of the course, you'll have built an extremely clean React Hook and published it to npm with multiple features, documentation, and a fully interactive example site. Along the way, you'll also learn best practices around using TypeScript with React Hooks.

Master Custom React Hooks with TypeScript

Build a powerful hook that enables complex functionality with just one line in a component of your choice.

Build a React Hook npm package with built-in TypeScript type declarations.

Build an example site that updates the hook's properties in real-time.

How to craft **custom React Hooks using TypeScript**

Importance of the **full lifecycle** (mount, unmount, and more) of React Hooks

How to **integrate TypeScript types** with custom React Hooks

What problems **TypeScript with React Hooks** can solve

How to create a **community-ready** custom React Hook package that is a **joy to use**

How to add basic functionalities including **Title Looping**, **Packaging the Module** using **Roolup**, and **Cleaning Up and Refactoring** just to name a few.

How to add advanced functionalities including the immplementation of **Cascading Letter**, **Marquee**, **Favicon Modification**, **Interval Time as a Hook Parameter**, and **Should Always Plas as Hook Parameter** just to name a few.

 How to implement optimization such as **Custom Types**, **Development-only Warning Logger**, preventing concurent usages of the Hook, restoring origional values on **Refocus** and **Unmount**, and more.

So far, you might have noticed that what happens when focus is restored to the web page using your hook has been mostly ignored. The same is true for the case if 

 is unmounted for some reason. For both cases, whatever iteration or current state of the 

 or the favicon were set at would remain that way for the page. This isn't a good developer experience. To remedy this problem, you can store the original values of both the 

 when the hook is used. When focus is restored to the page or 

 unmounts, you can restore those original values. This ensures a complete "leave no trace" life cycle. These changes will make it easy to mount and unmount your hook as needed without any extra coding effort from you as the developer using the hook.

// Modifies the document.title of the page when shouldIterateTitles is true
useTitleChangeEffect(
  titles,
  shouldIterateTitles,
  animationType,
  interval,
  shouldAlwaysPlay
);

// Modifies the favicon of the page when shouldIterateTitles is true
useFaviconChangeEffect(
  faviconLinks,
  shouldIterateTitles,
  interval,
  shouldAlwaysPlay
);

 to restore the original values when the component unmounts or focus is regained. Before anything, add the new 

export const useTitleChangeEffect = (
  titles: ArrayOfOneOrMore<string>,
  shouldIterateTitles: boolean,
  animationType: AnimationType,
  interval: number,
  shouldAlwaysPlay: boolean
) => {
  // ...
};

Then, introduce a new ref that you'll call 

 to store the original title of the page:

const originalTitleRef = useRef<string>(document.title);

 with the return cleanup function restoring the title:

// On unmount, restore the original title
useEffect(() => {
  return () => {
    document.title = originalTitleRef.current;
  };
}, []);

To handle the refocus case, you need to reset the title only in the case when 

// If shouldIterateTitles and shouldAlwaysPlay are both false, restore the original title
if (!shouldIterateTitles && !shouldAlwaysPlay) {
  document.title = originalTitleRef.current;
}

You also need to modify the original implementation of the switch case:

if (shouldIterateTitles || shouldAlwaysPlay) {
  switch (animationType) {
    case AnimationType.CASCADE:
      return runCascadeTitleLogic();
    case AnimationType.MARQUEE:
      return runMarqueeTitleLogic();
    case AnimationType.LOOP:
    default:
      return runLoopTitleLogic();
  }
}

, you need to add it to the dependency array of the 

[titles, titleIndex, shouldIterateTitles, shouldAlwaysPlay];

// Each time titleIndex changes and shouldIterateTitles is true, set the document.title to the value of titles at that index
useEffect(() => {
  if (shouldIterateTitles || shouldAlwaysPlay) {
    switch (animationType) {
      case AnimationType.CASCADE:
        return runCascadeTitleLogic();
      case AnimationType.MARQUEE:
        return runMarqueeTitleLogic();
      case AnimationType.LOOP:
      default:
        return runLoopTitleLogic();
    }
  }

  // If shouldIterateTitles and shouldAlwaysPlay are both false, restore the original title
  if (!shouldIterateTitles && !shouldAlwaysPlay) {
    document.title = originalTitleRef.current;
  }
}, [titles, titleIndex, shouldIterateTitles, shouldAlwaysPlay]);

---
title: Restore Original Values on Refocus and Unmount
code: https://gitlab.com/fullstackio/books/react-use-please-stay-with-react-and-typescript/-/blob/production/course/code/lesson-16
isPublicLesson: true
useMdx: true
privateVideoUrl: https://stream.mux.com/26k3XMrdaIOiLTw8H5Jyqjcnqru0201vLIZax9QuNUXto.m3u8
---

So far, you might have noticed that what happens when focus is restored to the web page using your hook has been mostly ignored. The same is true for the case if `usePleaseStay` is unmounted for some reason. For both cases, whatever iteration or current state of the `document.title` or the favicon were set at would remain that way for the page. This isn't a good developer experience. To remedy this problem, you can store the original values of both the `title` and `favicon` in `ref`s via the `useRef` when the hook is used. When focus is restored to the page or `usePleaseStay` unmounts, you can restore those original values. This ensures a complete "leave no trace" life cycle. These changes will make it easy to mount and unmount your hook as needed without any extra coding effort from you as the developer using the hook.

## Modifications to `usePleaseStay`

Starting at the top hook, `usePleaseStay`, you first need to forward on `shouldAlwaysPlay` to both `useTitleChangeEffect` and `useFaviconChangeEffect`:

```ts
// Modifies the document.title of the page when shouldIterateTitles is true
useTitleChangeEffect(
  titles,
  shouldIterateTitles,
  animationType,
  interval,
  shouldAlwaysPlay
);

// Modifies the favicon of the page when shouldIterateTitles is true
useFaviconChangeEffect(
  faviconLinks,
  shouldIterateTitles,
  interval,
  shouldAlwaysPlay
);
```

## Modifications to `useTitleChangeEffect`

Now, make the modifications to `useTitleChangeEffect` to restore the original values when the component unmounts or focus is regained. Before anything, add the new `shouldAlwaysPlay` parameter to the function signature:

```ts
export const useTitleChangeEffect = (
  titles: ArrayOfOneOrMore<string>,
  shouldIterateTitles: boolean,
  animationType: AnimationType,
  interval: number,
  shouldAlwaysPlay: boolean
) => {
  // ...
};
```

Then, introduce a new ref that you'll call `originalTitleRef` to store the original title of the page:

```ts
const originalTitleRef = useRef<string>(document.title);
```

To handle the unmount case, add a `useEffect` with the return cleanup function restoring the title:

```ts
// On unmount, restore the original title
useEffect(() => {
  return () => {
    document.title = originalTitleRef.current;
  };
}, []);
```

To handle the refocus case, you need to reset the title only in the case when `shouldAlwaysPlay` is `true`. Add this to the `useEffect` that handles the `shouldIterateTitles` case:

```ts
// If shouldIterateTitles and shouldAlwaysPlay are both false, restore the original title
if (!shouldIterateTitles && !shouldAlwaysPlay) {
  document.title = originalTitleRef.current;
}
```

You also need to modify the original implementation of the switch case:

```ts
if (shouldIterateTitles || shouldAlwaysPlay) {
  switch (animationType) {
    case AnimationType.CASCADE:
      return runCascadeTitleLogic();
    case AnimationType.MARQUEE:
      return runMarqueeTitleLogic();
    case AnimationType.LOOP:
    default:
      return runLoopTitleLogic();
  }
}
```

Now that you are making use of `shouldAlwaysPlay` within `useTitleChangeEffect`, you need to add it to the dependency array of the `useEffect`:

```ts
[titles, titleIndex, shouldIterateTitles, shouldAlwaysPlay];
```

Combined, the main `useEffect` in `useTitleChangeEffect` should look like this:

```ts
// Each time titleIndex changes and shouldIterateTitles is true, set the document.title to the value of titles at that index
useEffect(() => {
  if (shouldIterateTitles || shouldAlwaysPlay) {
    switch (animationType) {
      case AnimationType.CASCADE:
        return runCascadeTitleLogic();
      case AnimationType.MARQUEE:
        return runMarqueeTitleLogic();
      case AnimationType.LOOP:
      default:
        return runLoopTitleLogic();
    }
  }

  // If shouldIterateTitles and shouldAlwaysPlay are both false, restore the original title
  if (!shouldIterateTitles && !shouldAlwaysPlay) {
    document.title = originalTitleRef.current;
  }
}, [titles, titleIndex, shouldIterateTitles, shouldAlwaysPlay]);
```

Altogether, `useTitleChangeEffect` now looks like this:

```ts
import { useEffect, useRef, useState } from "react";
import { TAB_CHARACTER_COUNT } from "../constants/Constants";
import { AnimationType } from "../enums/AnimationType";
import { ArrayOfOneOrMore } from "../types/ArrayOfOneOrMore";
import { useInterval } from "./useInterval";

export const useTitleChangeEffect = (
  titles: ArrayOfOneOrMore<string>,
  shouldIterateTitles: boolean,
  animationType: AnimationType,
  interval: number,
  shouldAlwaysPlay: boolean
) => {
  const [titleIndex, setTitleIndex] = useState(0);
  const originalTitleRef = useRef<string>(document.title);

  const runLoopIterationLogic = () => {
    const nextIndex = titleIndex + 1;
    nextIndex === titles.length ? setTitleIndex(0) : setTitleIndex(nextIndex);
  };

  const runCascadeIterationLogic = () => {
    const nextIndex = titleIndex + 1;
    nextIndex === titles[0].length
      ? setTitleIndex(0)
      : setTitleIndex(nextIndex);
  };

  const runMarqueeIterationLogic = () => {
    const nextIndex = titleIndex + 1;
    nextIndex === TAB_CHARACTER_COUNT
      ? setTitleIndex(0)
      : setTitleIndex(nextIndex);
  };

  const runLoopTitleLogic = () => {
    document.title = titles[titleIndex];
  };

  const runCascadeTitleLogic = () => {
    document.title = titles[0].substring(0, titleIndex);
  };

Restore Original Values on Refocus and Unmount

Masterclasses

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Fullstack React with TypeScript