A React TODOs example, explained

The TODOs app is the new “Hello World”

I was asked to answer a Quora question about a simple TODOs example, and I thought a detailed explanation for it would be helpful to any one starting to learn React.

You can see the code in action (Make sure you execute it with ES6/Babel selected in the middle). I did not write that code, I am just going to explain it inline after each important concept. The example is a simple TODOs app with 3 components:

• TodoList (the container and state manager)
• TodoItems (presentational for the list of todos)
• TodoInput (controlled component to read a new todo)

The first rendered interface looks like:

The initial list renders with test items “red” and “blue”, then you can use the “Add” button to add more items to the list. Thanks for reading!