Code 301 Reading Notes

Class 01

React is a flexible JavaScript library for creating user interfaces.
Each React component is encapsulated and can operate independently.
The React Devtools extension for Chrome and Firefox lets you inspect a React component tree with your browser's developer tools.
To collect data from multiple children, or to have two child components communicate with each other, one must declare the shared state in their parent component instead. The parent component can pass the state back down to the children by using props; this keeps the child components in sync with each other and with the parent component.
Tic Tac Toe - Codepen

The smallest React example looks like this:

ReactDOM.render(
  <h1>Hello, world!</h1>,
  document.getElementById('root')
);

It displays a heading saying “Hello, world!” on the page.

Things to consider when reading React documentation:

We define variables with let and const statements. For the purposes of the React documentation, you can consider them equivalent to var.
We use the class keyword to define JavaScript classes. There are two things worth remembering about them. Firstly, unlike with objects, you don't need to put commas between class method definitions. Secondly, unlike many other languages with classes, in JavaScript the value of this in a method depends on how it is called.
We sometimes use => to define "arrow functions". They're like regular functions, but shorter. For example, x => x * 2 is roughly equivalent to function(x) { return x * 2; }. Importantly, arrow functions don't have their own this value so they're handy when you want to preserve the this value from an outer method definition.

to be continued...

to be continued...

to be continued...