Become a member
to unlock all features

Level Up!

Access all courses & lessons on egghead today and lock-in your price for life.


    Write More Reusable React Components with Composable APIs

    Joe MaddaloneJoe Maddalone
    0.14 - 16

    To make more composable React components, you can define common APIs for similar component types.



    Become a Member to view code

    You must be a Member to view code

    Access all courses and lessons, track your progress, gain confidence and expertise.

    Become a Member
    and unlock code for this lesson




    When creating React components one key tenet should be that your components should be reusable as well as composable. Now here in our code view we've got the slider component that we created in the refs video, so hopefully you guys saw that, but basically we've got these slider components that we can drag around and they update their value. What I'm going to do is strip these down, or strip this down to just one slider component. So I'll go ahead and get rid of the rest of these guys.

    When we save that, we can see it's not such a great component, we don't even necessarily need a component for this guy, but what we're going to do is we're going to rename this to numinput, we're going to create a more composable, more reusable component, taking advantage of the similar APIs between the number input and the range input. So to get us started I'm going to create some prop types, so we've got numinput.proptypes, set that to an object and for the sake of brevity I'm just going to paste these in, we'll take a quick look at them.

    We've got min set to a number, max set to a number, step and value set to a number. We've got a property of label set to a string, and that's going to allow us to take this label right here out of the control of the user and put it into the control of the component. We've got our update method which is our only required method and that has a type of function, and then finally we've got a type property which is type of oneof, which takes in an array, and we are willing to accept number or range as a string.

    Now we're going to go and set up our numinput default props, and again I'm just going to paste these in for the sake of brevity. We've got min and max both set to a default of 0step set to 1, val set to 0label set to an empty string, and for a default we're going to use range. Now here in our component, going to paste in some initial settings. So our type, min, max, step, and default value are all set to the props that are passed into our component, our update method does not change, we need to implement our label which we'll drop right here after the input.

    We may want to come back and make an option to have that be before or after the input. So to implement that I'm just going to say let label = thisprops.label <> '' and if that's the case, we'll go ahead and output a label tag, we won't worry about the for value, and it's innerHTML will be this.props.label, and just for this demo, we'll go ahead and also output this.props.val otherwise it will just be an empty string. We'll go and save that.

    So up here where we're utilizing that, we won't need this label right here, go ahead and break this out a bit so we can see. Set our min = 0our max = 255, our step = 1, our value = this.state.red and we're going to need to coerce that into a number since the component is expecting a number. We'll set our label to red. So let's go ahead and save that and try it out. We've got our slider, and we've got our label, and we've got our value.

    If we wanted to come over here and update our type to be a type of number input, now we've got our number input and everything seems to be working just fine. If we want to mess around and say this our step of 001 we can do that. That will step by .01. If we want to switch that back to the default of range, now you can see it is in fact stepping by that decimal value. So now we have a component that's much more reusable and much more composable.