React.JS — Component Data Transfer – codeburst

  • If you are passing data from somewhere in a component, to somewhere else inside the same component, this can be done through state.So what is state?The heart of every React component is its “state”, an object that determines how that component renders behaves.
  • That might look something like this:class component_A extends Component { constructor() { super(); this.state = { data: [], };}In this case, we are defining the state of data.
  • Passing data from parent to child components is only slightly trickier, in that, we can’t pass data in an unbroken chain to other components.
  • [callback] in the child, and pass in the data as an argument.From our above example, our code might look something like this:class component_A extends Component { constructor() { super(); this.state = { listDataFromComponent_C: “ “, };}myCallback = (dataFromComponent_C) = {this.setState({ dataFromComponent_C: dataFromComponent_C});Now from within the child component (component_C) we can pass something to props are static, while state can be changed, once you have passed data from a child to a parent, or from parent to a child, you may need to interact with it differently within that new component.
  • It might look like the following:class component_A extends Component {constructor = {dataFromComponent_C: “ “};},myCallback = (dataFromComponent_C) = {this.setState({ dataFromComponent_C: dataFromComponentC });This is just a brief explanation of how to change data within a component, and transfer data to other child and parent components.

In React JS, there’s often a need to pass data from one component to another. If you are passing data from somewhere in a component, to somewhere else inside the same component, this can be done…
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React.js: The Hard Parts

State Management without #Redux:  #ReactJS #Javascript

  • If a user interacts with your application or refreshes the page, then we’ll look up state at that moment and rebuild the page.
  • In dynamic apps, like ones built using React, state change has to be dealt with immediately.
  • Managing state can get complicated if each component has some state.
  • Interaction with the components, like a mouse click, trigger these functions to update state.
  • For example to implement retweets:

    When the state is updated, the props will change too and render the child components again.

I am a full-stack software developer and passionate educator. I have been building for the web for almost two decades.
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8 things to learn in React before using Redux

  • A component can manage a whole lot of state, pass it down as props to its child components and pass a couple of functions along the way to enable child components to alter the state in the parent component again.
  • Component A is the only component that manages local state but passes it down to its child components as props.
  • In addition, it passes down the necessary functions to enable B and C to alter its own state in A.

    Now, half of the local state of component A is consumed as props by component C but not by component B.

  • When you lift the local state management down to component C, all the necessary props don’t need to traverse down the whole component tree.
  • When a library such as Redux “connects” its state managements layer with React’s view layer, you will often run into a higher order component that takes care of it (connect HOC in react-redux).

Facts about React that should be known before using Redux (or MobX). Most important: Learn React first, then opt-in Redux…
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Beginners Guide into ReactJS

  • See React as HTML inside Javascript which brought about JSX(Javascript XML) we’ll discuss more on that later.
  • A React component is a single object that not only outputs HTML like a traditional template would, but also includes all the code needed to control that output.
  • As you can see, the component approach means that both HTML and JavaScript code live in the same file.
  • In React, mutable state is typically kept in the state property of components, and only updated with , They are referred to has

    Let’s quickly go through the below code.

  • The render method consist of a form element that has an input field and also a submit button below, The input field has the onChange function that takes in , this method takes in as a parameter which happens to be the DOM event handler, and gets the result from , is one of the component API methods which is use to update state value, with this as a user types into the input field, the value will be updated in state.

Dive into React with this Quick Start Guide. Differences between Props and State
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React.js: The Hard Parts

  • If a user interacts with your application or refreshes the page, then we’ll look up state at that moment and rebuild the page.
  • In dynamic apps, like ones built using React, state change has to be dealt with immediately.
  • Managing state can get complicated if each component has some state.
  • Interaction with the components, like a mouse click, trigger these functions to update state.
  • For example to implement retweets:

    When the state is updated, the props will change too and render the child components again.

I am a full-stack software developer and passionate educator. I have been building for the web for almost two decades.
Continue reading “React.js: The Hard Parts”

8 things to learn in React before using Redux

  • A component can manage a whole lot of state, pass it down as props to its child components and pass a couple of functions along the way to enable child components to alter the state in the parent component again.
  • Component A is the only component that manages local state but passes it down to its child components as props.
  • In addition, it passes down the necessary functions to enable B and C to alter its own state in A.

    Now, half of the local state of component A is consumed as props by component C but not by component B.

  • When you lift the local state management down to component C, all the necessary props don’t need to traverse down the whole component tree.
  • When a library such as Redux “connects” its state managements layer with React’s view layer, you will often run into a higher order component that takes care of it (connect HOC in react-redux).

Facts about React that should be known before using Redux (or MobX). Most important: Learn React first, then opt-in Redux…
Continue reading “8 things to learn in React before using Redux”

Code your own combineReducers – Jakob Lind

New post! Code your own combineReducers function.  #reactjs #redux #javascript

  • A reducer is a function that takes the Redux state and a Redux Action as input parameters.
  • The combineReducer function call takes an object with reducers.
  • We now have the function combineReducers that accepts reducers as input parameters.
  • As we learned in the beginning in this article, a normal Redux reducer is a function that takes two parameters: state and action.
  • The output after running getState should be an object with all the reducer names as keys and the state as the value.

It’s time for a completely different approach. To master Redux, we will code it from scratch. Today it’s time for the combineReducer function.
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