Learn Chrome-devtools and Html

WAI-ARIA, the Accessible Rich Internet Applications Suite, defines a way to make Web content and Web applications more accessible to people with disabilities. It especially helps with dynamic content and advanced user interface controls developed with Ajax, HTML, JavaScript, and related technologies. 

aria

Debug Computed Accessibility Properties with Chrome Dev Tools

In this lesson, we use the element inspector in Chrome to test and improve our contrast to meet WCAG AA Contrast Ratio Standards.

Resources:
- [WebAIM - Contrast and Color Accessibility](https://webaim.org/articles/contrast/)

Debugging Accessible Contrast with Chrome Dev Tools

JavaScript® (often shortened to JS) is a lightweight, interpreted, object-oriented language with first-class functions, most known as the scripting language for Web pages, but used in many non-browser environments as well such as node.js or Apache CouchDB. It is a prototype-based, multi-paradigm scripting language that is dynamic, and supports object-oriented, imperative, and functional programming styles.

javascript

We'll discuss the minimum set of files that are required to get up and running with Vue.

We'll add an `index.html` file as our entry point, a `main.js` file that will contain our JavaScript code and a `styles.css` that will contain all of our CSS. We also load Vue into our project with UNPKG which exposes the Vue object to us.

Set up the Minimum Files Needed to Run Vue 3

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

html

We'll round out the HTML for our form fields by adding radio buttons and checkboxes, including each in a checked, unchecked and disabled state. You'll learn about best practices for both field types semantically as well as when to use each.

Radio buttons should be used when you want a single selection out of a set of options while checkboxes should be used when you want multiple selections out of a set. A key difference between radio/checkbox and other inputs is that you wrap the label around the options which creates a direct relationship between the label and input so a `for` attribute is not strictly necessary.

Create Semantic, Accessible HTML for Radio Buttons and Checkboxes

Continuing on from our text inputs, we'll make our next field type including a select with the `multiple` attribute. Additionally, we'll include these fields in a disabled state. Both types will use the `.form-group` created in the previous lesson for a touch of layout styling.

You'll notice the same pattern here as with text inputs in that to make select inputs fully semantic and accessible you will need to add a `for` attribute that matches the `id` of the select element

Create Semantic, Accessible HTML for Form Selects

Learn how to ensure accessibility of text form inputs from the start by defining semantic HTML. To do this, we'll need a label for each input that we create. This label needs to be associated with the input through a `for` attribute which allows screen readers to know that a label is associated as well as allows a click of the label to focus the input.

We'll create HTML for text and textarea, as well as disabled versions of both.

Create Semantic, Accessible HTML for Text Form Inputs

Learn how to make a fully functioning Tic Tac Toe game that doesn't need any client-side JavaScript!

For this course, we'll be using Pug and Stylus which are preprocessors for HTML and CSS respectively.

Learn how to:
- Generate markup with loops and template literals
- Leverage native HTML behavior
- Create SVG
- Use CSS variables and scope
- Implement game logic with HTML forms
- Animate SVG with CSS
- Use CSS Animation to provide motion
- Use Pug Mixins
- Disable motion when users don't want it
- Apply visual effects using CSS filter and backdrop-filter
- Generate random animations using Pug and CSS variables

Cascading Style Sheets bring order and beauty to our applications.

Tic Tac Toe with CSS and SVG

If you're repeating blocks of markup or code in Pug, you can use a mixin to reduce the maintenance overhead. Here, we look at some of the ways you can use Pug mixins.

Use Pug Mixins for Reusable Blocks of Markup

We can use SVG to create a cross with one path. But, what if want to animate a cross as if it's being hand-drawn? We can do this by defining more than one path for our SVG.

Use SVG to Create an Animatable Cross

Use the circle element in SVG to define a radius and center points for a circle.

Use SVG to Create a Circle

Use SVG to create lines with the path element. We can hand-code a path definition and set a stroke width and stroke linecap. We can adjust the path definition to accommodate for the SVG viewBox.

Use SVG to Create Lines

You can use an element with the type "reset" within a form to reset a form on click. It's particularly useful when we don't want users to refresh a page in order to get back to an initial state.

Use Type Reset to Reset Form State

Use the HTML preprocessor Pug to generate markup for a form. Here we generate a set of labels and checkboxes. We link these using ES6 Template Literals with a loop index.

Use Pug For Loops to Generate Form Markup

The CSS filter property lets us apply the power of SVG filter effects to HTML elements. One little-known effect included in modern browsers is [`<fePointLight>`](https://developer.mozilla.org/en-US/docs/Web/SVG/Element/fePointLight). We'll use it together with `<feDiffuseLighting>` to add a light source to an `<h1 />` element.

Add a Light Source with CSS and the fePointLight SVG Filter

The Chrome Developer Tools (DevTools for short), are a set of web authoring and debugging tools built into Google Chrome.

chrome-devtools

Lighthouse is a tool that analyses web apps and web pages, collecting modern performance metrics and insights on developer best practices.

It's built directly into the Chrome DevTools and in this quick lesson we're going to learn how to run the audit, how to read its results and why you should always run the Lighthouse audit in Incognito mode.



Run a Lighthouse audit in Chrome Devtools

Sometimes you encounter a backend issue which seems to occur only on your computer, with a very specific sets of headers, cookies etc. Because of that, it's useful to have a way of easily sharing network requests sent by your browser with other members of your team.

In this quick lesson we're going to learn how to copy a network request as `fetch` (so we can test it in the Chrome DevTools console/in a node.js script) or as cURL (so we can test it in a terminal).

Copy a network request as fetch or cURL with Chrome DevTools

Sometimes when debugging our CSS styles it's useful to be able to see what a DOM element is going to look like in a given state (e.g. `:focus`, `:active, `:hover`) etc.

Unfortunately it's not possible to both hover over an element and debug it in Chrome DevTools at the same time (since we only have a single cursor!).

In this quick lesson we're going to learn how to address this problem by explicitly forcing an element state to `:hover` with DevTools

Force a DOM element state in Chrome DevTools

In this exercise, we will be going over 2 examples of when to use aria-hidden (hint: decoration) and when to use hidden.

In the first example, we will be hiding a "middle dot" that we have for formatting. This middle dot isn't necessary to be read out, so we add an aria-hidden attribute on that span.

When we use hidden, we will completely hide things from the viewport AND the screen reader.

aria-hidden vs. hidden

In this lesson, we explore using Chrome's DevTools to detect unwanted visual instability on a page.

We can do this using the new "Experience" heading under recorded "Performance" metrics.

To truly see the impact of "[Cumulative Layout Shift](https://web.dev/cls/)", we can make use of DevTools' "Network throttling" feature to see any visual instability with the naked eye.



Use Chrome DevTools to Detect Cumulative Layout Shift

Check out the new and currently experimental "CSS Overview" feature in Chrome's DevTools.

Use it to get an overview of details such as colors, fonts, media queries, and even unused declarations.

Explore a Site's CSS with Chrome DevTools CSS Overview

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



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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