javascript - 使用自定义 Knockout 映射时获取索引值

Question

我正在像这样设置一个 Knockout ViewModel:

var Schedule = function(data, parent) {
    var self = this;
    ko.mapping.fromJS(data, {}, self);
    self.foo = 'bar';
    ...
};

var ScheduleViewModelMapping = {
    'schedules': {
        create: function(options) {
            return new Schedule(options.data, options.parent);
        }
    }
};

ko.mapping.fromJS(data, ScheduleViewModelMapping, self);

$(document).ready(function() {
    var ViewModel = new ScheduleViewModel;
    ko.applyBindings(ViewModel);
});

Schedules 是一个数组，我希望能够在某处获取当前计划的索引，这样我就可以将它与 options.data 和 options.parent 一起传递给 Schedule 对象。

Answer 1

我建议更改您的映射处理程序，以便它可以存储一些状态:

var ScheduleViewModelMapping = new (function(){
    var counter = 0;

    this.schedules = {
        create: function(options) {
            //use counter as index as required
            var s = new Schedule(options.data, options.parent);
            counter++;
            return s;
        }
    }

    this.resetCounter = function() {
        counter = 0;
    }
})();


ScheduleViewModelMapping.resetCounter();
ko.mapping.fromJS(data, ScheduleViewModelMapping, self);