JSX

Instead of create custom components by Root.createElement, we can use JSX to crate react component.

There are three parameters needed to create a react component: type, properties, children, they passed to the JSX through the type of the dom element, element properties and the children element:

<CustomComponent props = {props}>
    {shoudHasChild && <Child childProps = {childProps}></Child>}
</CustomComponent>

And, can use some operator like && whin the {}, just like the JSX component is a variable. So that, the JSX can also create from a stream using map, which generates a list of JSX component.

Note, that here is a special prop: key react use that to identify a component, which means that there will only render one component for each different key.