@ZackArgyle 1. Start with plain React. 2. Lift state as needed. 3. Still feeling pain? Use Redux/Context/etc.

  • Currently, both components independently keep their values in the local state: – – However, we want these two inputs to be in sync with each other.
  • Since the props of both components are coming from the same parent component, the two inputs will always be in sync.
  • It will handle the change by modifying its own local state, thus re-rendering both inputs with the new values.
  • For example, if we enter 37 into the Celsius input, the state of the component will be: – – If we later edit the Fahrenheit field to be 212, the state of the will be: – – We could have stored the value of both inputs but it turns out…
  • The inputs stay in sync because their values are computed from the same state: – – Try it on CodePen.

Often, several components need to reflect the same changing data. We recommend lifting the shared state up to their closest common ancestor. Let’s see how this works in action.
Continue reading “@ZackArgyle 1. Start with plain React.
2. Lift state as needed.
3. Still feeling pain? Use Redux/Context/etc.”

Writing Easily Testable Code with Stateless Components in React.js

Writing Easily Testable Code with Stateless Components in #React.JS  #javascript #testing

  • The use of Stateless Functional Components (a.k.a. “pure” or “dumb” components) in React.js continues to grow since first it was released in React 0.14, and for good reasons.
  • By relying on pure components, developers end up writing reusable code that’s extremely easy to test, which leads to better application architecture.
  • Personally, I like the term “pure component” because it’s indicative of what the code really is — a pure function sprinkled with some JSX.
  • In addition to these benefits, pure components also make it extremely easy to test code with any crazy props that you wish.
  • As we just saw, the code for functional components provides us awesome intel for everything we need to know in order to write effective tests.

Functional Stateless Components provides clean syntax that allows us to write more declarative code. We will look at stateless components and finish up with some unit tests in this article.
Continue reading “Writing Easily Testable Code with Stateless Components in React.js”

Writing Easily Testable Code with Stateless Components in React.js

  • The use of Stateless Functional Components (a.k.a. “pure” or “dumb” components) in React.js continues to grow since first it was released in React 0.14, and for good reasons.
  • By relying on pure components, developers end up writing reusable code that’s extremely easy to test, which leads to better application architecture.
  • Personally, I like the term “pure component” because it’s indicative of what the code really is — a pure function sprinkled with some JSX.
  • In addition to these benefits, pure components also make it extremely easy to test code with any crazy props that you wish.
  • As we just saw, the code for functional components provides us awesome intel for everything we need to know in order to write effective tests.

Functional Stateless Components provides clean syntax that allows us to write more declarative code. We will look at stateless components and finish up with some unit tests in this article.
Continue reading “Writing Easily Testable Code with Stateless Components in React.js”

Higher Order Components in React – CloudBoost

Higher Order Components in React  #higherordercomponents #react #reactjs #javascript #reactjs

  • We must find a way to abstract that repetitive logic in order to avoid going through our codebase every time we want to make a change.What are Higher Order Components?As the name suggests — a Higher Order Component is some special and more important component.
  • If you’ve ever used map, reduce or filter you have already used HOF without even knowing.Similarly to that – Higher Order Components take a component as input and return another component.
  • Some of the more Object Oriented programmers will immediately scream “inheritance”, but have in mind that React favors composition.How do we make a HOC?Let’s start simple and make a HOC that we will use to log the clicks of our users.Here our function takes the component we will be wrapping as an argument and returns a brand new component with all the attached functionality to it.
  • To create our new component we will simply call the function and pass the wrapped one as a parameter.const LogsClicks = else can we do with HOCs?Higher Order Components can be used every time you’ve got repetitive logic in your components.
  • Now when the component mounts and every time it updates, our component will now look at the authenticated property and will redirect to the home page if it’s false.Something to note is that when we’re using the connect helper in order to attach our component to Redux’s store, we are creating another Higher Order Component.

Components are the building blocks of React. We separate our UI into small pieces that are responsible for rendering and managing the state of a particular part of the application. But even though…
Continue reading “Higher Order Components in React – CloudBoost”

Better Form Management – Robbie Dela Victoria – Medium

Better Form Management  #javascript #react #reactjs

  • Better Form ManagementBuilding complex forms in react.js is notoriously hard, there are a lot of moving parts.
  • Don’t forget A/B testing, if you’re into that sort of thing.After rebuilding the form below a few times, I’ve come up with a few general tips to help manage the complexity of forms.
  • The goal of this series of articles is to help guide you through the process of creating a better form.

Building complex forms in react.js is notoriously hard, there are a lot of moving parts. Not only do you have to manage the state of the each input (values), you have to manage the validation and…
Continue reading “Better Form Management – Robbie Dela Victoria – Medium”

Functional Components in React – ziv zamechek – Medium

Functional Components in React  #javascript #react #reactjs

  • We are setting the state with key term and the new value of the input.
  • The component renders, the value of the input is set to retrieve the value from this.state.term so its initial value is an empty string.
  • Whenever setState is called the event will re render and the value of the input will receive the new value of this.state.term finally the component finishes rendering and the new value of the input is finally visible on the screen.
  • It also allows us to read the value of the input much more easily.The most parent component that is concerned with a piece of information to be responsible for fetching it.
  • Then the callback function with data will be called with the list of videos.The object that we are passing has a key of videos and the value is videos that is passed as an argument.We can condense this using ES6 when key and variable name are the same we can just use the value name which is videos in this case, for example:this.setState({ videos: videos }); is the same as: this.setState({ videos });So the list of videos on the state starts as an empty array but the instance of the component that is rendered kicks off a search when the search is complete it will update the value with the new list of videos.Thank You

So basically the function onChange will run because it is the event handler. We are setting the state with key term and the new value of the input. Whenever we update the state it will cause the…
Continue reading “Functional Components in React – ziv zamechek – Medium”

How to Create a Redux Form with Validation and Initialized Values

Create a Redux-Form with validation and initialized values:  #ReactJS #Redux #JavaScript

  • Even better, with the latest release candidate (Redux Form 6.0.0rc3) and later, you can upgrade to the latest version of React and not have those pesky errors bring your project to a screeching halt.
  • This tutorial is going to help you set up a Redux Form that uses the latest syntax, and how to get that form set up with some simple validation and initial values.
  • Open up your console and use to install the Redux Form release candidate:

    Our tutorial will also be dependent on and , so make sure you have the latest versions of those installed as well.

  • So just underneath our dependencies, outside of the scope of the component, add the following:

    Handling the validation of our form can get messy if we do it “inline” as part of the render function of our component.

  • So to clean that up and make it reusable (plus easier to manage), create a that returns the input and logic for any errors that our field receives:

    Let’s also create a similar constant that will serve our input:

    Now we need to define the redux form required property inside the render function of the component.

With the latest version of redux form available we take a look at the best way to create a form that starts with pre-populated fields and validation.
Continue reading “How to Create a Redux Form with Validation and Initialized Values”