箭头函数几个模版例子（便于自己查询）

// ES5

    var selected = allJobs.filter(function (job) {

      return job.isSelected();

    });

 // ES6

    var selected = allJobs.filter(job => job.isSelected());

// ES5

    var total = values.reduce(function (a, b) {

      return a + b;

    }, 0);

// ES6

    var total = values.reduce((a, b) => a + b, 0);

 // ES5

    $("#confetti-btn").click(function (event) {

      playTrumpet();

      fireConfettiCannon();

    });

 // ES6

    $("#confetti-btn").click(event => {

      playTrumpet();

      fireConfettiCannon();

    });