time aspect using generic aspect implementation

GenericTimeAspect.js

function timeAspect(joinPoint, logger) {
    const timer = {
        start: function () { this.startTime = Date.now() },
        stop: function () { this.stopTime = Date.now() },
        time: function () { return this.stopTime - this.startTime }
    };

    function before() { timer.start() }
    function after() { timer.stop(), logger.log(timer.time) }
    return aspect(joinPoint, { before, after })
}

expensiveCalculation = timeAspect(expensiveCalculation, console);