1, No comment
I don't like to write comment for each of statement/function/class even before I heard the concept "clean code". Almost developers I work with don't think that's good idea.
2, Short variable name
I still like to name the variables with just one letter in the contexts (usually local) where the logic is clear and easy to understand. For example:
var formatCurrency = (num) => {
let n = Number(num);
if (!n || !bella.isNumber(n) || n < 0) {
return '0.00';
}
return n.toFixed(2).replace(/./g, (c, i, a) => {
return i && c !== '.' && (a.length - i) % 3 === 0 ? ',' + c : c;
});
};
Many developers I work with with don't think that's good idea.