Microservices with Docker, Flask, and React

  • To connect the client to the server, add a method to the class: – – We’ll use Axios to manage the AJAX call: – – You should now have: – – To connect this to Flask, open a new terminal window, navigate to the flask-microservices-users, activate the virtual environment, and…
  • Kill the Create React App server, and then run: – – We still need to call the method, which we can do in the : – – Run the server – via – and then within Chrome DevTools, open the JavaScript Console.
  • What would happen if the AJAX request took longer than expected and the component was mounted before it was complete?
  • Finally, update the method to display the data returned from the AJAX call to the end user: – – Let’s create a new component for the users list.
  • Add a new file to that folder called UsersList.jsx: – – Why did we use a functional component here rather than a class-based component?

If you’re new to React, review the Quick Start and the excellent Why did we build React? blog post. You may also want to step through the Intro to React tutorial to learn more about Babel and Webpack.
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I wish I knew these before diving into React – OpsGenie Engineering

  • By default, setState triggers a re-renderThe default behavior of React is to re-render on every state change, and most of the time it is okay to rely on this.
  • However, re-rendering unnecessarily wastes cycles which is not a good practice.Each component has a method called shouldComponentUpdate and it is called everytime you change state or pass new props from the parent component.
  • We can simply divide lifecycle into three parts:Mounting: an instance of the component is being created and inserted into the DOM.Updating: component is being re-rendered, can be caused by changes of props or state.Unmounting: component is being removed from the DOM.It is very important to understand how these methods work….
  • Compare this.props with nextProps and if there is a significant change, act on it.Two important notes here:React may call componentWillReceiveProps even if the props have not changed, so comparing this.props and nextProps is is invoked before a mounted component receives new props, this means React doesn’t call componentWillReceiveProps with initial…
  • Use React Developer ToolsReact Developer Tools lets you inspect the React component hierarchy, components’ props and state.

At OpsGenie, we had a deep dive into React for our Badges project. I learned many new things & made many mistakes. These are the things that really helped me.
Continue reading “I wish I knew these before diving into React – OpsGenie Engineering”

How to use React Lifecycle Methods » Andreas Reiterer

How to use #ReactJS Lifecycle Methods:  by @a_reiterer #JavaScript #Code

  • React components have several “lifecycle methods” that allow us to execute actions (e.g.: fetching data from a server) at particular times.
  • There are three particular stages in the lifecycle of a component, that are important for our lifecycle methods, which I will explain: – – When React creates an instance of a component and inserts it into the DOM (mounting), the following methods are called: – – If props or state…
  • That process is called unmounting and means that the following method is called: – – I hope I could give you a short overview of the life of a React component and the calling order of lifecycle methods.
  • Some people suggest to use it for doing some configuration of the root component that you can only do at runtime (e.g.: setting up a Firebase connection) – – Whenever this method is called, React has already rendered our component and put it into the DOM.
  • This means, it could be possible that the method returns false but React still decides to re-render the component.

Use React lifecycle methods to perform actions on mount, update and unmount of a component. Learn more about e.g. componentDidMount and when to use it
Continue reading “How to use React Lifecycle Methods » Andreas Reiterer”

How to use React Lifecycle Methods » Andreas Reiterer

  • React components have several “lifecycle methods” that allow us to execute actions (e.g.: fetching data from a server) at particular times.
  • There are three particular stages in the lifecycle of a component, that are important for our lifecycle methods, which I will explain: – – When React creates an instance of a component and inserts it into the DOM (mounting), the following methods are called: – – If props or state…
  • That process is called unmounting and means that the following method is called: – – I hope I could give you a short overview of the life of a React component and the calling order of lifecycle methods.
  • Some people suggest to use it for doing some configuration of the root component that you can only do at runtime (e.g.: setting up a Firebase connection) – – Whenever this method is called, React has already rendered our component and put it into the DOM.
  • This means, it could be possible that the method returns false but React still decides to re-render the component.

Use React lifecycle methods to perform actions on mount, update and unmount of a component. Learn more about e.g. componentDidMount and when to use it
Continue reading “How to use React Lifecycle Methods » Andreas Reiterer”

How to use React Lifecycle Methods » Andreas Reiterer

  • React components have several “lifecycle methods” that allow us to execute actions (e.g.: fetching data from a server) at particular times.
  • When React creates an instance of a component and inserts it into the DOM (mounting), the following methods are called:

    If props or state of a component are changed for whatever reason, an update of the component is performed.

  • That process is called unmounting and means that the following method is called:

    I hope I could give you a short overview of the life of a React component and the calling order of lifecycle methods.

  • Some people suggest to use it for doing some configuration of the root component that you can only do at runtime (e.g.: setting up a Firebase connection)

    Whenever this method is called, React has already rendered our component and put it into the DOM.

  • This means, it could be possible that the method returns false but React still decides to re-render the component.

Use React lifecycle methods to perform actions on mount, update and unmount of a component. Learn more about e.g. componentDidMount and when to use it
Continue reading “How to use React Lifecycle Methods » Andreas Reiterer”

Ch 10 “React Native” is new to React in Action @ManningBooks @MarkTheThomas #react

Ch 10

  • React is an open source JavaScript framework that lets you quickly create user interfaces for web applications.
  • It also utilizes a component-focused design, so you can build large, robust web applications that scale well with users and developers.
  • Reasoning about an interface or application written with React ends up being much easier because it decreases overall complexity for developers working with it.
  • Large and small companies alike are using React for highly-visible, high-impact applications including Facebook.com, Netflix.com, and Airbnb.com.
  • “An up-to-date and very comprehensive book on React, not only limited to React itself but also discusses how it can be integrated with other tools and frameworks.”

React is an open source JavaScript framework that lets you quickly create user interfaces for web applications. This highly-performant tool implements a one-way data flow model, which means communication is much more top-down than side-to- side. It also utilizes a component-focused design, so you can build large, robust web applications that scale well with users and developers. Reasoning about an interface or application written with React ends up being much easier because it decreases overall complexity for developers working with it. Large and small companies alike are using React for highly-visible, high-impact applications including Facebook.com, Netflix.com, and Airbnb.com.
Continue reading “Ch 10 “React Native” is new to React in Action @ManningBooks @MarkTheThomas #react”

#React in Action teaches you to use the #reactjs framework #JavaScript @MarkTheThomas

#React in Action teaches you to use the #reactjs framework  #JavaScript @MarkTheThomas

  • Reasoning about an interface or application written with React ends up being much easier because it decreases overall complexity for developers working with it.
  • Large and small companies alike are using React for highly-visible, high-impact applications including Facebook.com, Netflix.com, and Airbnb.com.
  • React in Action introduces front-end developers to the React framework and related tools.
  • In the second section, you’ll explore the different ways that data works in React as well as learning more about components.
  • In the last section, you’ll explore React application architecture with Redux, server-side rendering, and even dabble in React Native.

React is an open source JavaScript framework that lets you quickly create user interfaces for web applications. This highly-performant tool implements a one-way data flow model, which means communication is much more top-down than side-to- side. It also utilizes a component-focused design, so you can build large, robust web applications that scale well with users and developers. Reasoning about an interface or application written with React ends up being much easier because it decreases overall complexity for developers working with it. Large and small companies alike are using React for highly-visible, high-impact applications including Facebook.com, Netflix.com, and Airbnb.com.
Continue reading “#React in Action teaches you to use the #reactjs framework #JavaScript @MarkTheThomas”