CocosCreator实现文字逐个出现的打字机效果

typingAni: function (label, text, cb) {
        var self = this;
        var html = '';
        var arr = text.split('');
        var len = arr.length;
        var step = 0;
        self.func = function () {
            html += arr[step];
            label.string = html;
            if (++step == len) {
                self.unschedule(self.func, self);
                cb && cb();
            }
        }
        self.schedule(self.func,0.05, cc.macro.REPEAT_FOREVER, 0)

    },