debug.js

function toTest(a, b) {
    return a + b
}

function debug(fn) {
    return function() {
        console.log(`Going to call ${fn.name} with ${[].slice.call(arguments).join(', ')}`)
        result = fn.apply(this, arguments)
        console.log(`Got result from ${fn.name} of`, result);
        return result
    }
}

debug(toTest)(1,2)