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”

Redux, Immutability, and Higher Order Components

Redux, immutability, and higher order components:  #ReactJS

  • A higher order component is exactly what it sounds like — it is the React component equivalent of a higher order function.
  • In React, a higher order component is a function that accepts a component and returns an enhanced component with superhero abilities.
  • A simple example of a higher order function in Haskell that takes a function and applies it twice to something.
  • , connect() is, through mapDispatchToProps() , subscribing the TodoList component to a change handler that will toggle a todo when the todo is clicked.
  • Well, arguably, one of the key concepts when using Redux with React lies in a higher order component: connect() .

Read the full article, click here.


@ReactiveConf: “Redux, immutability, and higher order components: #ReactJS”


As I wrote in a previous blog post, immutability is an important concept that can bring many benefits to development. In fact, it’s been embraced by javascript land, most notably by the ultra-popular framework, Redux.


Redux, Immutability, and Higher Order Components