Learn Angular, Chai and Typescript

course repository: https://github.com/ducin/egghead-typescript/tree/brand-types-value-objects

TypeScript is a typed superset of JavaScript that compiles to plain JavaScript.

typescript

Domain Data Modelling using TypeScript Aliases, Brand Types and Value Objects

This course is perfect for those looking for a lightweight alternative to NgRx Store that scales effortlessly.

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.

Scalable Signals Angular Architecture with NGRX Signal Store

In this lesson you will learn how to verify if some literal value satisfies any given type or not. There are two ways to do this i.e. either by declaring a variable of some given type and assigning it the value or we can use the `satisfies` keyword. We will take an example and look at both of the ways in this video.

Verify if some literal value satisfies a given type

A queue is FIFO (First In First Out) list. When you remove elements from the queue, oldest item is removed first. In this lesson we'll cover how to implement a queue using TypeScript. Queue based questions are common in technical interviews, so it useful to be familiar with how they work.

Build a Queue data structure in TypeScript

A stack is LIFO (Last In First Out) list. When you remove elements from the list, the most recently added item is removed first. In this lesson we'll cover how to implement a stack using TypeScript. Stack based questions are common in technical interviews, so it useful to be familiar with how they work.

Create the Stack data structure using TypeScript

Use the Typescript keyof operator to create a custom type based of an object

We'll learn how to calculate the number of Nodes in a Linked List.

Return the Length of a Linked List

In this lesson we'll learn how to search through a Linked List to find the index of a Node with a given value.

Find the Index of a Linked List Node by Value

We'll learn how to get the value of a Node in a Linked List at a given Index.

Get the Value of a Linked List Node by Index

We'll learn how to remove a Node from a Linked List at a given Index.

Delete a Linked List Node at a given Index in TypeScript

We'll learn to how add a new elements to a linked list at a specific index.

Insert values into a TypeScript Linked List with insertAt

In this lesson we'll cover the basic elements of a linked list and how to append nodes to one.

Create a Linked List in TypeScript

There might be times when you want to extend a type, i.e., to add new fields to it. Instead of copying the types and creating duplicates, the better way to do that is to use the intersection operator `&`. In this quick lesson, you will learn what it does and how you can use it to reduce duplicate types.

Merge Types using Intersection Operator

Fix TypeScript Errors related to Function Type Parameters and Generic Constraints

Filter TypeScript Unions of Primitives or Objects depending on the usecase

angular

Using Angular's `toSignal` function with the HTTP client enables components to reactively fetch and display data from external services. 

This approach simplifies code and handles undefined initial values, but note that `toSignal` immediately subscribes and makes the HTTP request when used. So, keep in mind if you're using it in a component or some root level service.

Fetch Data via HTTP Using RxJS Observables and toSignal

The `toSignal` function in Angular enables the conversion of an RxJS observable into a signal. 

It allows you to wrap an observable and handle the initial value of the resulting signal. You can explicitly define the initial value, require a synchronous emission from the observable, and more! 

Turn an RxJS Observable Into an Angular Signal With toSignal

Angular's `toObservable` function enables converting signals to RxJS observables. This allows creating observable properties that stay synchronized with signal values. 

Whenever the signal value changes, the corresponding observable emits a notification, facilitating the interoperability between signals and observables.

Turn an Angular Signal Into an RxJS Observable

In Angular, effects are often assigned to class properties during the constructor phase. However, there may be cases where the effect needs to be parameterized with values from parent components, which are not available during construction.

When running effects outside the constructor, such as in the `ngOnInit` lifecycle hook, you need to manually provide the `injector` instance to the `effect` configuration.

Bind an Angular Signal Effect to an Injector for Automatic Cleanup

Angular provides a `manualCleanup` configuration option for effects, preventing automatic cleanup when the owner component/service is destroyed. 

With `manualCleanup: true`, you gain control but must manually call `.destroy()` on the `EffectRef` that is returned by your `effect` to release resources like intervals or subscriptions. 

Remember, with great power comes great responsibility!

Destroy an Angular Signal Effect Automatically or Manually

Sometimes you will need to properly clean up your effects to prevent memory leaks. Like if you use timeouts or intervals. 

Implement cleanup logic using the `onCleanup` callback. In your effect you can call `onCleanup`, pass it a callback, and define actions like clearing intervals or unsubscribing from observables when effects are no longer needed. 

Set up an Angular Signal Effect Cleanup Handler



Discover how to harness the power of Cursor IDE's Composer Agent feature to optimize your code. In this lesson, you'll witness an AI agent doing all the work to generate test suites, implement performance benchmarks, and create optimized function variations - all without writing a single line of code. You'll learn how to validate performance improvements through data-driven benchmarking, ensuring that optimizations are backed by concrete metrics rather than speculation. This hands-on demonstration showcases a groundbreaking approach to automated function development that combines the precision of test-driven development with the efficiency of AI-powered optimization.


Agent-Driven Development in Cursor: Testing, Benchmarking, and Optimizing Functions

This course is aimed for using `zod` effectively in projects based on TypeScript (both browser and node.js). The benefits you gain with this course is not just simply coding, but also understanding when/why/how should you perform runtime validation.

`zod` is the missing piece to TypeScript's capabilities, which can guarantee type-safety only in compile-time.

`zod` can be used whenever the compiler cannot guarantee what happens in runtime. And... it's a very frequent usecase, such as HTTP calls, websockets, etc.

In this course you get quickly up and running by:
1. using `zod` with primitives and objects
2. adapting `zod` quickly to existing projects thanks to automatic generators
3. changing the strategy frm type-first to schema-first
4. using error-throwing `parse` or non-error-throwing `safeParse` basing on your needs
5. applying `zod` to the most common usecase - validating API responses
6. handling errors the most convenient way (out of many!)

Take advantage of runtime validation with `zod`. Take advantage of the detailed lessons in this course 🔥

Effective Runtime Type Checks with Zod


Cursor can now automatically run commands in the terminal and walk step-by-step towards building out your entire project. You give it a goal, then it will suggest the commands you need to run and the files that you need to create and you can work with it to achieve what you're building. This lesson does a quick walkthough of using a Cursor Agent to build a project from scratch and guide it along the way. Cursor Agents definitely feel like a sneak peek at the future of programming!

Cursor Agents Initial Impressions - Allow an AI to Build Your Entire Project

Mock Service Worker is an API mocking library that allows you to write client-agnostic mocks and reuse them across any frameworks, tools, and environments.



Mocking WebSocket APIs with Mock Service Worker


While using anonymous functions might seem convenient, they can create difficulties when trying to identify performance bottlenecks during profiling. This lesson will demonstrate how named functions make it easier to pinpoint and address performance issues, ultimately leading to more efficient and debuggable code. Learning this practice will greatly improve your ability to locate and fix performance issues in complex projects.

Always Name Functions in JavaScript


When attempting to load the same module twice in JavaScript you'll hit a cache and code won't re-run. In scenarios where you actually do want to have state in your modules, you'll have to use a cache-busting technique by passing a query parameter to a dynamic import. This lesson walks through how to add a query parameter, how to add the appropriate types for loading dynamic modules in TypeScript, and when these techniques are valuable.

Import the Same JavaScript Module Multiple Times with Cache Busting



The include keyword in GitHub Actions empowers you to add custom variables to your matrix strategy, providing flexibility beyond standard configurations. In this video, we'll explore how include allows you to define specific combinations of variables, enhancing control over your workflow runs. You'll see how this feature enables you to tailor jobs for unique environments or scenarios not covered by the default matrix options. By leveraging include, you can efficiently manage complex build processes with greater precision. This technique helps you streamline your CI/CD pipeline, making it more adaptable to your project's evolving needs.

Use GitHub Actions Matrix Include for Complex Job Configurations

While running `zod` schema validation agains domain-rich objects, the error message saying that _a string is not a number_ might not be really useful.

Especially, when you need to provide a meaningful feeback to the user, e.g. after they have submitted a form with lots of data.

`zod` allows to customize messages on a very granular level. We can also extract repeatable customization to `zod` error maps.

Finally, in order to process an error message further (e.g. display it to the user), we need to handle the `zod` validation errors effectively. Especially, when a big object validation has failed and we could receive a handful of errors.

That's what we learn in this lesson. 🔥

Customize zod Error Messages and Handle zod Errors Effectively

customize zod validation messages, customize zod schema property messages, reuse error maps across different schemas, navigate through zod error objects

You might want to run `zod` schema checks in different styles.

Sometimes you prefer to conditionally throw the error - that's what `parse` does. But another time you'd prefer to receive a `boolean` property that determines whether the validation was successful or not - and perform further actions accordingly.

Additionally, the error-throwing API of `parse` works extremely well with [TypeScript assertion functions](https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-7.html#assertion-functions). Their combination is just... perfect! 👌

That's what we learn in this lesson.

Use parse and safeParse Runtime Type-checks with zod

use zod parse function to conditionally throw ZodError, use zod safeParse to get a boolean value and run typescript type guard over success property

In this lesson we learn that TypeScript cannot guarantee correct shapes of responses. That's due to TS performing checks in compile-time, while the response will be availbale in runtime - when TS doesn't exist anymore.

In some situations, such as HTTP requests, runtime type checks such as `zod` are essential for providing quick feedback around data-related errors.

Understand where are the possible mistakes to make while using TypeScript with HTTP calls. Use `fetch` and `axios` along with `zod` schema checks.

Also, note that similar mistakes or mistakes could happen while using web storage (e.g. `localStorage`)

Validate HTTP API Response with zod, fetch and axios

use zod as an HTTP response validation tool along with fetch and axios in order to make sure that the response has expected data structure

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