Count all arguments of a function (including arguments with default values)
The native length method of an ES function returns the number of the function arguments, e.g. function(a, b) {}).length is 2. But if the function knows arguments with default values, those are not included. So
function x(a, b=2, c=3) {};
console.log(x.length); // => 1;
This small utility library also counts the arguments with default values.
This will always be an approximation, good for almost all cases but it may not be accurate for edge cases (like very complex strings/strings within values that are Objects, function declarations as parameters etc.).
Use import countArguments from '//kooiinc.github.io/ESCountArguments/CountArgumentsLib.js' to use this utility.
See this Stackblitz project for tests and syntax