console.log not a function when passed as an argument to some other function and called within

Question

I'm attempting to build my own for loop construct.

function loop(value, test, update, body) {
    if (test(value)) {
        body(value);
        return loop(update(value), test, update);
    }
}

The error the Edge browser is giving me:

VM1297:3 Uncaught TypeError: body is not a function
    at loop (<anonymous>:3:3)
    at loop (<anonymous>:4:10)
    at <anonymous>:1:1

Using this call:

loop(10, n => n > 0, n => n - 1, console.log)

Why does JS not see body as a function?

Answer 1

You were not passing body as last parameter in next iteration. You should do loop(update(value), test, update, body); instead of loop(update(value), test, update);

 function loop(value, test, update, body) { if (test(value)) { body(value); return loop(update(value), test, update, body); } } loop(10, n => n > 0, n => n - 1, console.log)