@ -74,9 +74,9 @@ There are two types of "model" data in React: props and state. It's important to
## Step 3: Identify the minimal (but complete) representation of UI state
To make your UI interactive you need to be able to trigger changes to your underlying data model. React makes this easy with **state**.
To make your UI interactive, you need to be able to trigger changes to your underlying data model. React makes this easy with **state**.
To build your app correctly you first need to think of the minimal set of mutable state that your app needs. The key here is DRY: *Don't Repeat Yourself*. Figure out what the absolute minimal representation of the state of your application needs to be and compute everything else you need on-demand. For example, if you're building a TODO list, just keep an array of the TODO items around; don't keep a separate state variable for the count. Instead, when you want to render the TODO count simply take the length of the TODO items array.
To build your app correctly, you first need to think of the minimal set of mutable state that your app needs. The key here is DRY: *Don't Repeat Yourself*. Figure out what the absolute minimal representation of the state of your application needs to be and compute everything else you need on-demand. For example, if you're building a TODO list, just keep an array of the TODO items around; don't keep a separate state variable for the count. Instead, when you want to render the TODO count simply take the length of the TODO items array.
Think of all of the pieces of data in our example application. We have:
@ -131,7 +131,7 @@ So far we've built an app that renders correctly as a function of props and stat
React makes this data flow explicit to make it easy to understand how your program works, but it does require a little more typing than traditional two-way data binding. React provides an add-on called `ReactLink` to make this pattern as convenient as two-way binding, but for the purpose of this post we'll keep everything explicit.
If you try to type or check the box in the current version of the example you'll see that React ignores your input. This is intentional, as we've set the `value` prop of the `input` to always be equal to the `state` passed in from `FilterableProductTable`.
If you try to type or check the box in the current version of the example, you'll see that React ignores your input. This is intentional, as we've set the `value` prop of the `input` to always be equal to the `state` passed in from `FilterableProductTable`.
Let's think about what we want to happen. We want to make sure that whenever the user changes the form we update the state to reflect the user input. Since components should only update their own state, `FilterableProductTable` will pass a callback to `SearchBar` that will fire whenever the state should be updated. We can use the `onChange` event on the inputs to be notified of it. And the callback passed by `FilterableProductTable` will call `setState()` and the app will be updated.
@ -139,4 +139,4 @@ Though this sounds like a lot it's really just a few lines of code. And it's rea
## And that's it
Hopefully this gives you an idea of how to think about building components and applications with React. While it may be a little more typing than you're used to, remember that code is read far more than it's written, and it's extremely easy to read this modular, explicit code. As you start to build large libraries of components you'll appreciate this explicitness and modularity, and with code reuse your lines of code will start to shrink :)
Hopefully this gives you an idea of how to think about building components and applications with React. While it may be a little more typing than you're used to, remember that code is read far more than it's written, and it's extremely easy to read this modular, explicit code. As you start to build large libraries of components, you'll appreciate this explicitness and modularity, and with code reuse your lines of code will start to shrink. :)
@ -78,9 +78,9 @@ There are two types of "model" data in React: props and state. It's important to
## Step 3: Identify the minimal (but complete) representation of UI state
To make your UI interactive you need to be able to trigger changes to your underlying data model. React makes this easy with **state**.
To make your UI interactive, you need to be able to trigger changes to your underlying data model. React makes this easy with **state**.
To build your app correctly you first need to think of the minimal set of mutable state that your app needs. The key here is DRY: *Don't Repeat Yourself*. Figure out what the absolute minimal representation of the state of your application needs to be and compute everything else you need on-demand. For example, if you're building a TODO list, just keep an array of the TODO items around; don't keep a separate state variable for the count. Instead, when you want to render the TODO count simply take the length of the TODO items array.
To build your app correctly, you first need to think of the minimal set of mutable state that your app needs. The key here is DRY: *Don't Repeat Yourself*. Figure out what the absolute minimal representation of the state of your application needs to be and compute everything else you need on-demand. For example, if you're building a TODO list, just keep an array of the TODO items around; don't keep a separate state variable for the count. Instead, when you want to render the TODO count simply take the length of the TODO items array.
Think of all of the pieces of data in our example application. We have:
@ -135,12 +135,12 @@ So far we've built an app that renders correctly as a function of props and stat
React makes this data flow explicit to make it easy to understand how your program works, but it does require a little more typing than traditional two-way data binding. React provides an add-on called `ReactLink` to make this pattern as convenient as two-way binding, but for the purpose of this post we'll keep everything explicit.
If you try to type or check the box in the current version of the example you'll see that React ignores your input. This is intentional, as we've set the `value` prop of the `input` to always be equal to the `state` passed in from `FilterableProductTable`.
If you try to type or check the box in the current version of the example, you'll see that React ignores your input. This is intentional, as we've set the `value` prop of the `input` to always be equal to the `state` passed in from `FilterableProductTable`.
Let's think about what we want to happen. We want to make sure that whenever the user changes the form we update the state to reflect the user input. Since components should only update their own state, `FilterableProductTable` will pass a callback to `SearchBar` that will fire whenever the state should be updated. We can use the `onChange` event on the inputs to be notified of it. And the callback passed by `FilterableProductTable` will call `setState()` and the app will be updated.
Let's think about what we want to happen. We want to make sure that whenever the user changes the form, we update the state to reflect the user input. Since components should only update their own state, `FilterableProductTable` will pass a callback to `SearchBar` that will fire whenever the state should be updated. We can use the `onChange` event on the inputs to be notified of it. And the callback passed by `FilterableProductTable` will call `setState()` and the app will be updated.
Though this sounds like a lot it's really just a few lines of code. And it's really explicit how your data is flowing throughout the app.
## And that's it
Hopefully this gives you an idea of how to think about building components and applications with React. While it may be a little more typing than you're used to, remember that code is read far more than it's written, and it's extremely easy to read this modular, explicit code. As you start to build large libraries of components you'll appreciate this explicitness and modularity, and with code reuse your lines of code will start to shrink :)
Hopefully this gives you an idea of how to think about building components and applications with React. While it may be a little more typing than you're used to, remember that code is read far more than it's written, and it's extremely easy to read this modular, explicit code. As you start to build large libraries of components, you'll appreciate this explicitness and modularity, and with code reuse your lines of code will start to shrink. :)
@ -170,7 +170,7 @@ Notice how we're mixing HTML tags and components we've built. HTML components ar
### Using props
Let's create the `Comment` component, which will depend on data passed in from its parent. Data passed in from a parent component is available as a 'property' on the child component. These 'properties' are accessed through `this.props`. Using props we will be able to read the data passed to the `Comment` from the `CommentList`, and render some markup:
Let's create the `Comment` component, which will depend on data passed in from its parent. Data passed in from a parent component is available as a 'property' on the child component. These 'properties' are accessed through `this.props`. Using props, we will be able to read the data passed to the `Comment` from the `CommentList`, and render some markup:
Elaine Fang
10 years ago