I guess I'm not very good at JavaScript.
This is how I've seen react components initialised. The initial set state is done within the constructor.
export class Counter extends React.Component {
constructor(props) {
super(props);
this.state = {count: props.initialCount};
}
why is there always a super(props). Is this required? Is calling super necessary at all? What would happen if super isn't called?
You need to pass props in super only if you want to access this.props in constructor of the class.
class Base extends React.Component {
constructor(props) {
console.log('Base', props);
}
render() {
return <div>Base {this.props.name}</div>;
}
}
class Sub extends Base {
constructor(props) {
super({
name: 'New name prop'
});
console.log('Sub', arguments);
}
}
var sub = <Sub name="Gomic" />
React.render(sub, document.getElementById('container'));
Props are by default not assigned in the constructor. They are assinged in the method React.createElement. So super(props) should be called only when the superclass's constructor manually assings props to this.props. When you just extend the React.Component calling super(props) method will do nothing with props.
Reference:
