Please anyone can explain this React code, how is work?

Question

This is React code and this works perfectly but the problem is I can't understand how this works. If anyone knows how this works please explain it to me.

This is the query = ?cid=619386618c57a571f4463d45&type=page

export default (query) => {
    if(query){
        const queryString = query.split("?")[1];
        if(queryString.length > 0){
            const params = queryString.split("&");
            const paramObj = {};
            params.forEach(param => {
                const keyValue = param.split("=");
                paramObj[keyValue[0]] = keyValue[1];
            });
            return paramObj;
        }
    }

    return {};
}

Answer 1

There is almost zero react here. It is quite plain JavaScript

export default (query) => {
    if(query){ // if there is a string 
        const queryString = query.split("?")[1]; // get the stuff after the ?
        if(queryString.length > 0){ // if there was stuff after the ? 
            const params = queryString.split("&"); // split on & (gives an array)
            const paramObj = {}; // create an object
            params.forEach(param => { // for each part of the split array 
                const keyValue = param.split("="); // split on the = 
                paramObj[keyValue[0]] = keyValue[1]; // use the string before the = as key and after as value 
            });
            return paramObj; // return the object
        }
    }

    return {}; // otherwise return empty object
}