Learn Chrome-devtools, Flux-architecture and Redux-observable

Handling async actions that affect your application’s state sounds like a tall order, but Redux makes it possible — and a win-win for you and your app’s users.

In this course, we will begin with nothing more than an empty directory and a text editor. Through small, focused lessons, we’ll learn how to set up a React project that uses Redux for state management and redux-observable for asynchronous actions. We’ll see how ‘epics’ are registered and how they each receive a ‘stream’ of actions from the store.

With an understanding of how things work, we’ll move onto solving common problems like: 
- Ajax cancellation
- creating sequences of async actions
- enabling code reuse through higher-order Observables 
- and much more.

RxJS 5-based middleware for Redux. Compose and cancel async actions to create side effects and more.

redux-observable

Asynchronous State Management with redux-observable v1

Chrome DevTools are incredibly useful for a frontend developer, sometimes we spend more time using them than our text editor of choice.

That's why it's so important to understand this tool better - those quick lessons will teach you things that will help you to become a more effective developer.

You will learn how to:

- **Use (experimental) CSS Overview to learn all about CSS used on a page in a minute**
- **Style console.log messages with CSS** - a _crucial_ skill for any senior developer (j/k)
- **Debug your code (on production and local environment) with logpoints**
- **Run a Lighthouse audit of your site**
- **Choose accessible colors for your website that have an AAA contrast ratio rating**
- **Force a DOM element state in Chrome DevTools**
- **Use Console utilities to make debugging easier**
- **Copy a network request as fetch or cURL with Chrome DevTools**

Have fun!

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

chrome-devtools

Chrome DevTools tips & tricks

Miscellaneous one-off lessons on debugging, productivity hacks, and JavaScript tricks.

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

Tips and Tricks

Frontend runtime optimization is heavily impacted by rendering.  Understanding the way the JS engine and the browser work is crucial for optimizing applications and understading how to avoid performance pitfalls.
This collection explains about the Critical Rendering Path, performance bottlenecks and practical solutions.

Critical Rendering Path

***Note: RxJS imports have changed since the publication of this course. Operators now must be passed into `.pipe` to be applied to an observable.***

In this course we will begin with nothing more than an empty directory & a text editor. Through small, focussed lessons we’ll learn how to setup a React project that uses Redux for state management and redux-observable for asynchronous actions. We’ll see how ‘epics’ are registered and how they each receive a ‘stream’ of actions from the store. 

With an understanding of how things work, we’ll move onto solving common problems such as Ajax cancellation, creating sequences of async actions, enabling code reuse through higher-order Observables and much more. 

## **UPDATE:** 
This course is outdated, view updated material here: [Asynchronous State Management with redux-observable v1](https://egghead.io/courses/asynchronous-state-management-with-redux-observable-v1)

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

If you know what you’re doing, React can drastically simplify how you build, use, and maintain code.

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

Up and Running with redux-observable

In this course we’ll take a deep look at the Elements panel in the chrome devtools. We’ll step through each button and tab on this panel and discuss how to use them to interact with your web application as it runs.

Debug the DOM in Chrome with the Devtools Elements Panel

This course examines the Sources panel in the Chrome DevTools, which allows you to see what files are responsible for the various things on the screen. Bundled into this panel, though, is the single most useful tool for any JavaScript developer - the JavaScript Debugger. We’ll use the Debugger to inspect JavaScript as it runs, allowing you to watch (and even interact with) the state of your application as it runs in ways that’ll blow your mind if you’ve mostly used console.log to debug your applications to this point. 

Debug JavaScript in Chrome with DevTool Sources

This course will examine the Network panel in Chrome DevTools. We’ll step through the request log, examining the various properties exposed. We’ll talk about timing, filtering, throttling and generally using the network panel to better understand the ways in which our applications exist within a connected context.

Debug HTTP with Chrome DevTools Network Panel

If you are developing JavaScript applications you are likely using logging as an integral part of your development process. Did you know that you aren't limited to simple `console.log` statements? Modern browsers give you a lot more logging options to work with!

This course will explore those options and give you some new logging tools for your professional toolbox.

Advanced Logging with the JavaScript Console

Get more mileage from your console output by going beyond mere string logging - log entire introspectable objects, log multiple items in one call, and apply C-Style string substitution to make the console work for you.

Advanced Console Log Arguments

Organize your log output by grouping your logs into collapsable hierarchies using console.group().

Grouping and Nesting Console Log Output

Redux is a predictable state container for JavaScript apps.
It helps you write applications that behave consistently, run in different environments (client, server, and native), and are easy to test.

redux

In this lesson we’ll learn exactly what’s needed to incorporate redux-observable into an existing React/Redux application. We’ll learn what ‘Epics’ are, and how they receive a stream of actions and return a stream of actions. In-between is where we get to apply side-effects, call out to external services etc etc. In this lesson we’ll demonstrate the ‘async’ nature of epics by responding to an action with another, delay action.

Add redux-observable to an existing Redux project

In this lesson we’ll learn how to perform an Ajax request to an external API in response to an action in the redux store. We’ll see how, within the epic, we get access to actions after any reducers have been executed and how we can convert that incoming action into a resulting one that will save the data received into the redux store.

Use redux-observable for simple Ajax requests

With redux-observable, we have the power of RxJS at our disposal - this means tasks that would otherwise be complicated and imperative, become simple and declarative. In this lesson we’ll respond to an action by queuing up 2 separate Ajax requests that will execute sequentially. Then we’ll group the results from both into an array and produce a single action from our epic that will save the data into the redux store

Create a queue of Ajax requests with redux-observable and group the results.

When accepting user input and converting it into a request that talks to the outside world, we can often end up in a situation where responses are no longer relevant. This is a common case in type-ahead style input fields - we would only want to call an external search API after the user has stopped typing for a short amount of time. In this lesson we’ll see how we can begin to combine RxJS operators to solve such problems. 

Debounce user input to avoid repeated Ajax requests

Any application that uses external services such as APIs should be able to handle errors gracefully. Often this requires no more that displaying a message to the user and ensuring the application continues to function. In this lesson we’ll look at how we can convert an error from the network into an action that is dispatched into the Redux store, allowing us to show an error message to the user and prevent the application from crashing.

Handle network errors gracefully

Although ‘epics’ in RxJS are often described as ‘actions in, actions out’, there may be times when you need to ‘bail out’ of an action, or to just ignore the current one given some condition. By learning about RxJS’s `filter` Operator, we’ll see how easy it is to do ‘nothing’ when you need to. We’ll also see how the composition techniques available in RXJS allow us to control the UI in a declarative manner.

Filter a stream to exclude empty values

In certain situations, you care more about the final state of the redux store than you do about the particular stream of events coming out of an epic. In this lesson we explore a technique for dispatching actions direction into the store, having the epic execute as they would normally in production, and then assert on the updated store’s state.

Use tests to verify updates to the Redux store

 AJAX allows us to send requests to the server from our javascript applications, rather than allowing the browser to directly request declaratively specified resources. Under the hood, though, AJAX requests are still just HTTP requests - and that means we can use the Network Panel in Chrome’s DevTools to inspect our AJAX operations!


Examine AJAX Requests with Chrome Devtools

To understand the Network DevTool, you have to understand what HTTP is and how it works. Let’s use the Network DevTool to inspect an HTTP request and its corresponding response so that we can understand what the browser is doing.

Analyze HTTP Requests and Responses with Chrome Devtools

Go beyond console.log by learning about log levels, filtering log output and structuring your output to be meaningful and concise. The JavaScript console object offers many methods to make your life easier - start learning them here!

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