/**
 * Measures the runtime of given callable function
 * Second argument is optional, and puts an identifier string in front of console.log
 */
function timePerformance(callable) {
    // Identifier string to differentiate timings
    var identifier = arguments[1] || 'Time';

    // Start time
    var t0 = performance.now();

    // Run the function, log any results
    var result = callable();
    if(result) {
        console.log(result);
    }

    // End time
    var t1 = performance.now();

    // Log out the timing
    var runtime = (t1 - t0).toFixed(3);
    console.log(identifier + ": " + runtime + " milliseconds");

    return runtime;
}