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    Advanced React Component Patterns Update

    Use Redux with Render Props

    Kent C. DoddsKent C. Dodds

    Now that we have everything wired up to share and update the state of the toggled boolean across our application, let's see how easy it would be to change from the state of a single boolean to state in a redux store! We’ll call it rendex (render props + redux). 😍



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    Instructor: 00:00 As fun as it is to update the state of a Boolean, that is controlled throughout our entire application using this cool provider and our connected toggle thing. It even reaches through shoot component update is false. That's a pretty cool accomplishment, but it's only one Boolean.

    00:17 What if we could store our entire application state in this way? The de facto for storing application state is Redux. We're going to create rindex with this toggle provider, and the connected toggle, and out toggle component. We'll switch it over to a rindex component.

    00:35 The first thing we need to do is add Redux to our page. Let's go ahead and add a script tag for Redux. Then I'm going to take every instance of toggle on the page, and replace it with rindex. We'll do the same thing for our lowercase t toggle with rindex. Let's begin our refactor.

    00:56 Instead of default on, we're going to have initial state. That's going to default as an object. Our initial state is going to come from this.props.initialState. We're going to change from onRindex to onUpdate. Then let's create our store.

    01:12 We'll say store=redux.createStore. We're going to create our own root reducer. We'll initialize it with our initial state. Our root reducer is going to be a function that takes state and an action, and returns this.props.reducer, state, and action. Just for the fun of it, we'll make reducer, e, a function that takes state and returns state.

    01:39 Let's update the reset. Instead of isOnControlled, we'll change this to isStatecontrolled. Instead of this.props.on, we'll say state on our props, here and here, and then in the case that our state is controlled, we'll just call this.props.onReset with this.initialState.

    02:00 If it's not controlled, then we'll call, with a special action with a type rindexReset, and we'll get rid of this setState stuff. Then in our root reducer, we'll handle that. We'll say if the action type is rindexReset, then we will return this.initialState.

    02:23 Luckily for us, we don't need this toggle function, which is now rindex, or get rindex or props. We don't need those anymore. We have a mechanism for updating the state, and that's dispatch.

    02:35 One thing we do need is a componentDidMount. When the component mounts, we need to subscribe. We'll say, and every time there's an update, we'll say this.setState, with

    02:51 We don't want a memory leak, so we'll say this.unsubscribe equals the result of calling that function. Then we'll say componentWillUnmount, and call this.unsubscribe.

    03:02 Our render function is going to be a little bit different. We don't need these things anymore. We do want that reset, and we're definitely going to want a dispatch is .store.dispatch. The state is what we want. Instead of the onState, we'll just get the regular state. We'll get it from props if it's controlled, and if it's not, then we'll get it from the store.

    03:23 Let's update our rindex provider. It's rendering the rindex component, accepts a rindex object, and that is the value for react-broadcast. Our connected rindex is going to subscribe to our rindex provider's channel. It accepts a rindex, and renders with the rindex.

    03:41 Then we have the withRindex higher-order component. It renders a connected rindex, and that render prop accepts a rindex, and renders the component with rindex. Our update blocker remains unchanged.

    03:53 My input now uses connected rindex with the render prop, and instead of on, we're actually going to just accept rindex. Rindex is going to have our state, and we'll set that up in our Redux store here in a little bit.

    04:08 Instead of rindex, we're going to call rindex.dispatch. We'll make a type toggle and the value of true and false. In my switch, instead of getting on here, we'll get rindex.state.on. We'll say rindex.dispatch, with the type of toggle, and the value of notRindex.state.on.

    04:36 Our state printer, we'll get rindex, and it'll print out rindex.state. Our app uses the rindex provider. We don't need default on. We now need initial state, which will initialize to on is true. Let's see what we broke.

    04:52 Of course, we have a syntax error, and I knew I needed an extra parenthesis. We're getting an issue with getting state from undefined. That's because we're de-structuring rindex in my switch when rindex is the object that we get. Cool.

    05:06 Looks like state is now getting updated. That's because we don't yet have a reducer that handles actions of these types. Let's create our reducer.

    05:15 Reducer equals a function that takes state and action, and returns the state. We'll make a switch statement here, with action.type, and if it's toggle, then we'll return an object with the state, and on is going to be action.value. Otherwise, with the default case, we'll return the state. Now, I can toggle that on and off.

    05:43 For fun, let's add another case in our reducer input change. This will return our state, and input value will be action.value. We'll use this action type in our input at the bottom here. We'll say rindex.dispatch type input change, and the value is

    06:13 Now, "Hello, World!" and I could store anything in here that I like, using all the nice utilities from Redux. This was a pretty simple straight up refactor of a toggle component to a full-fledged Redux component.

    06:27 What this teaches us is that the patterns of render props, and state initializers, and controlled components, and the utility of react-broadcast are really powerful, and applicable in many scenarios, whether it be just a small, isolated component that you're going to reuse in multiple places, or a bigger component that controls state of the entire application.