Does jitsi meet use typescript?

I have fundamental on react but I have not seen any of following code fragment is available for react.
Does jitsi-meet include a post-compiler like typescript or anything else?
I try to search such package in package.json but could not found any.


Would appreciate if someone can help explaining where is following code fragment originated from?
is this es6, es7 or typescript? or is this something that available in react by default?

Note: i don’t know that we can do such static type declaration in react nor javascript

export type Props = {
   timestamp: any,
   url: Object | string

Note: Where does the Promise inherit from? And why do we need use promise here?

_init: Promise<*>;
componentDidMount() {

        this._init.then(() => {
            // If a URL was explicitly specified to this React Component, then
            // open it; otherwise, use a default.
            this._openURL(toURLString(this.props.url) || this._getDefaultURL());

Note: I didn’t know that we can declare the function params type in react nor javascript

componentDidUpdate(prevProps: Props) {

Even I had this same doubt. This definitely looks like typescript.

We don’t use typescript.

Those are Flow type annotations, which is what we currently use.

Hope that helps!