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frontend-bootcamp/step1-05/demo/README.md
2019-03-05 02:20:22 -08:00

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# Step 1.5 - Building a static page in React (Demo)
To start building our todo application, we'll follow the steps outlined in [Thinking in React](https://reactjs.org/docs/thinking-in-react.html). The first step of the process is to break our application into a component hierarchy. For this app, we're going to keep it simple and just use four parts.
- TodoHeader
- TodoList
- TodoListItem
- TodoFooter
You can find the HTML for our application in `step1-05/TodoApp.html`.
## TodoHeader
We'll store all of our components inside a `components` folder under `src`. Let's create that now. We'll then start writing the `TodoHeader` in `components/src/TodoHeader.tsx`. The `tsx` file extension tells our editor that this file includes React code written in TypeScript.
> We'll talk about TypeScript soon, but for now, know that all valid JavaScript is valid TypeScript.
```jsx
import React from 'react';
export class TodoHeader extends React.Component<any, any> {
render() {
return (
<header>
<h1>todos</h1>
<div className="addTodo">
<input className="textfield" placeholder="add todo" />
<button className="submit">Add</button>
</div>
<nav className="filter">
<button className="completed">all</button>
<button>active</button>
<button>completed</button>
</nav>
</header>
);
}
}
```
> Note that since this is React, we had to change `class` to `className`, but nothing else changes.
## TodoListItem
Any time you see repeated complex elements, that is usually a sign that you should create a new component. With a few props you can typically abstract all of those elements into a single component. This is certainly the case with todo items.
```jsx
import React from 'react';
export class TodolistItem extends React.Component<any, any> {
render() {
return (
<li className="todo">
<label>
<input type="checkbox" /> Todo 1
</label>
</li>
);
}
}
```
> Note that this control could also be created as a function instead of a class:
> ```jsx
> export const TodoListItem = (props) => {
> return (
> <li className="todo">
> <label>
> <input type="checkbox" /> Todo 1
> </label>
> </li>
> );
> }
> ```