Displaying a List of items with Redux

Objectives

With this lesson we'll finish up what we worked on the in the forms code along by displaying our list of todos. By the end of this lesson, you will be able to:

Display a list of elements from our Redux store

Goal

Our state is properly updating but we are not displaying these updates to the user. We need a component that references the store and then uses the data from the store to reference the list of Todos.

Displaying todos

The CreateTodo component is handling the creation side of things, so let's make a new component where we'll be getting todos from the store. We'll call this TodosContainer and connect it to Redux.

// ./src/components/todos/TodosContainer.js

import React, { Component } from 'react';
import { connect } from 'react-redux'

class TodosContainer extends Component {

  render() {
    return(
      <div></div>
    );
  }
};

export default connect()(TodosContainer);

Now, we aren't worried about dispatching actions here, only getting state from Redux, so we'll need to write out a mapStateToProps() function and include it as an argument for connect():

...
const mapStateToProps = state => {
  return {
    todos: state.todos
  }
}

export default connect(mapStateToProps)(TodosContainer);

We can confirm this is working by adding a log in the render of TodosContainer and then adding TodosContainer to our App component so it will be rendered.

Now that we have a way to get data from Redux, we can create a presentational component to handle displaying our todos.

Creating a Presentational Todo Component

To start, we'll have each todo rendered as a list item. Inside the ./src/components/ folder, create a file Todo.js. Inside it, write a functional component that returns an li displaying props:

// ./src/components/todos/Todo.js

import React from 'react'

const Todo = props => {
  return (
    <li>{props.text}</li>
  );
};

export default Todo;

Now we need to call that component from a map function in the TodosContainer component:

// ./src/components/todos/TodosContainer.js

import React, { Component } from 'react';
import { connect } from 'react-redux'
import Todo from './Todo'

class TodosContainer extends Component {

  renderTodos = () => this.props.todos.map((todo, id) => <Todo key={id} text={todo} />)

  render() {
    return(
      <div>
        {this.renderTodos()}
      </div>
    );
  }
};

const mapStateToProps = state => {
  return {
    todos: state.todos
  }
}

export default connect(mapStateToProps)(TodosContainer);

Now our TodosContainer is mapping over the todos it received from Redux, passing the value of each todo into a child component, Todo. Todo in this case doesn't have any Redux related code, and is a regular, functional component.

Cleanup Todo Input

Each time we submit a todo, we want to clear out the input. Ok, so remember that each time we submit a form, we call handleSubmit. Inside that handleSubmit function let's reset the component's state by changing our function to the following:

// ./src/components/todos/CreateTodo.js

...

handleSubmit = event => {
  event.preventDefault();
  this.props.addTodo(this.state)
  this.setState({
    text: '',
  })
}


...

That's it! We've got a working app that takes in form data and displays it on a list.

Summary

Ok, so we got our Todos component working simply by accessing the state from the store, and then iterating through the list in the Todos component.

References

React Documentation - Controlled Components

agiletkiewicz/redux-index-codealong-online-web-sp-000