// use attribute .tagName, which returns a type e.g. DIV, BUTTON, LI etc.
const functionName = () => {
    if(e.target.tagName == 'BUTTON') {
    console.log("It's a button";
    } else {
        console.log("It's not a button");
    }
}

// if you prefer: function functionName (params) {action} instead of "e.target" use this