React Higher-Order Components in TypeScript made simple

  • These attributes were chosen to illustrate all the aspects of HOCs while keeping the HOC as simple as possible.PropsThere are three types of props we need to consider when creating a HOC: OriginalProps, ExternalProps and InjectedProps.OriginalProps are props of the wrapped component.
  • The state of the HOC is simple, just the count of the clicksOptionsAs stated before, HOC is a function that takes a component and returns a component.While this is true, many HOCs take the form of curried HOC factories (like the mentioned connect from react-redux) that take a configuration object…
  • If you need to interact with props or states from here, the only way to do it is to specify options as functions, that take the props or states as arguments.For ClickCounted the options are simple – a flag indicating whether to console.log on click:Putting it all togetherHaving declared all the…
  • Now that we have the signature, all that’s left is to implement the HOC:First, we define the type alias for the resulting component’s props — the TOriginalProps ExternalProps to simplify its reuse.
  • Props and state are passed to it with whatever was in the OriginalProps along with the clickCount from the HOC state.Using the HOCTo illustrate how to use our HOC, we create a Demo component, that displays a different text depending on the amount of clicks and a custom message.Notice the type…

On a simple React Higher-Order Component, the process of writing them in TypeScript is demonstrated along with advice and rationals behind the type declarations
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Getting Started with React Native and Flow – React Native Training – Medium

Getting Started with React Native and Flow 📱👌 #javascript #react #reactnative #flowtype

  • Using the Flow server For a large project, you probably only want Flow to recheck files incrementally when they change.
  • To get started, we first need to make sure we either have flow set up in our project at node_modules/bin/flow (as we have already done above) or installed globally.
  • To stop the server, we can run node_modules/.bin/flow stop to stop the server.
  • In our project, we start the server by running node_modules/.bin/flow , which we’ve saved as an npm script npm run flow .

Flow allows us to easily add static type checking to our JavaScript. Flow will help you prevent bugs and allow for better code documentation among other things. A lot of the React Native…
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Building a React.js App: Component Validation with PropTypes

Building a React.js App: Component Validation with PropTypes by @tylermcginnis33  #React

  • So looking at how the repos component is being used, you’ll notice we’re passing in username and we’re passing in a repo .
  • Now you’ll notice we get this warning, “Failed propType required username was not specified in repos .”
  • We don’t have to have it required, but as we talked about earlier when we use repos, we basically need a username and a repos array for this, so let’s go ahead and now when we render our repos component, let’s go ahead and take out username and let’s see what happens.
  • If we come in and we just render the notes component list this,
  • So everything is working correctly, but now what we’ve done is we’ve made the userProfile , the repos , and the notes component all validate that they’re being used correctly .

In this video, we’ll add PropTypes to some of our existing components to ensure that each component gets the data it needs to function properly.
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