class say {
        constructor() {
        }

        sayHello() {
            console.log('hello');
        }

        get sayGoodbye() {
            console.log('goodbye');
        }

        static wocao() {
            console.log('wocao');
        }
    }

这样一个class
定义的property都是不可遍历的

看了下babel转码到es5的代码

var _createClass = function () {
    function defineProperties(target, props) {
        for (var i = 0; i < props.length; i++) {
            var descriptor = props[i];
            descriptor.enumerable = descriptor.enumerable || false;
            descriptor.configurable = true;
            if ("value" in descriptor) descriptor.writable = true;
            Object.defineProperty(target, descriptor.key, descriptor);
        }
    }

    return function (Constructor, protoProps, staticProps) {
        if (protoProps) defineProperties(Constructor.prototype, protoProps);
        if (staticProps) defineProperties(Constructor, staticProps);
        return Constructor;
    };
}();

function _classCallCheck(instance, Constructor) {
    if (!(instance instanceof Constructor)) {
        throw new TypeError("Cannot call a class as a function");
    }
}

注意到descriptor.enumerable = descriptor.enumerable || false; 这句
想知道怎么设置 descriptor.enumerable

    var say = function () {
        function say() {
            _classCallCheck(this, say);
        }

        _createClass(say, [{
            key: 'sayHello',
            value: function sayHello() {
                console.log('hello');
            }
        }, {
            key: 'sayGoodbye',
            get: function get() {
                console.log('goodbye');
            }
        }], [{
            key: 'wocao',
            value: function wocao() {
                console.log('wocao');
            }
        }]);

        return say;
    }();