javascript-如何通过复选框对模型的数组/内容实施多个过滤器

我正在尝试在同一模型上实现多个过滤器.我要应用过滤器的属性是数组.

//Exam Model
App.Exam = DS.Model.extend({
    name: DS.attr('string'),
    description: DS.attr('string'),
    courses : DS.hasMany('course',{ async: true }),

});

//Course Model
App.Course = DS.Model.extend({
 name: DS.attr('string'),
  description:DS.attr('string'),
  professors: DS.attr(),
  subjects: DS.attr(),
  languages: DS.attr(),
    exam: DS.belongsTo('exam', { async: true })
});

修改模型后,在ExamsExam路线中,提取要应用过滤器的数据.

App.ExamsExamRoute = Ember.Route.extend({
  model: function(params) {

    return this.store.find('exam', params.exam_id).then(function (exam) {
        console.log("found single exam", exam);
            return exam;
        });
  },

  afterModel: function(model, transition){
    var self = this;
    var professorList = [];
    var subjectList = [];
    var languageList = [];

    var promise = new Ember.RSVP.Promise(function(resolve, reject){
        var courses = model.get('courses');

        courses.forEach(function(course){
          self.store.find('course', course.get('id')).then(function(course){
            var profs = course.get('professors');
            var subjects = course.get('subjects');
            var languages = course.get('languages');

            profs.forEach(function(prof) {
              if (professorList.indexOf(prof) === -1) {
                professorList.pushObject(prof);
              }
            });

            subjects.forEach(function(subject) {
              if (subjectList.indexOf(subject)  === -1) {
                subjectList.pushObject(subject);
              }
            });

            languages.forEach(function(language) {
              if (languageList.indexOf(language)  === -1) {
                languageList.pushObject(language);
              }
            });
          });
        });
        var data = {
          professorList: professorList,
          subjectList: subjectList,
          languageList: languageList
        };
        resolve(data);
    });

    promise.then(function(data) {
      console.log(data);
      model.set('professorNameList', data.professorList);
      model.set('subjectList', data.subjectList);
      model.set('languageList', data.languageList);
    });
  }
});

这是我的模板

<script type="text/x-handlebars" data-template-name="exams/exam">
  <h2>Exam page</h2>
  <div class="row">
    <div class="col-md-3 well">
       <ul class="list-group well">
        {{#each course in model.languageList}}
         <li class="">
           <label>
            {{input type='checkbox'}}
            {{course}}
          </label>
        </li>
      {{/each}}
      </ul>

      <ul class="list-group well">
        {{#each prof in model.professorNameList}}
         <li class="">
           <label>
            {{input type='checkbox'}}
            {{prof}}
          </label>
        </li>
      {{/each}}
      </ul>


      <ul class="list-group well">
        {{#each subject in model.subjectList}}
         <li class="">
           <label>
            {{input type='checkbox'}}
            {{subject}}
          </label>
        </li>
      {{/each}}
      </ul>
    </div>


    <div class="col-md-9">
      {{#each course in model.courses}}
        <div class="well">
          Course name - {{course.name}}<br>
          Professors - {{course.professors}}<br>
          Subjects - {{course.subjects}}
        </div>
      {{/each}}
    </div>
  </div>

  </script>

现在,如何更改模型的内容,以便如果用户选择语言过滤器,则仅必须显示属于该所选语言的课程.
另外,如果用户选择语言和主题过滤器,则仅应显示与该条件匹配的过滤器.

关于通过ember中的复选框进行过滤的文档很少.

有人建议/指导我如何解决这个问题并获得一个干净的解决方案.

这是JS BIN DEMO,可以更好地说明我要实现的目标.

解决方法:

以@joostdevries的答案为基础…

将Every()与回调一起使用是一个很好的解决方案,但它“感觉”有些复杂.您要寻找的基本上是数组之间的交叉点.例如,模型中的普通教授既包含一系列选定的教授,也包含多个教授. Ember提供了这样的功能,称为…等待它……交集(请参阅here)：).它返回一个包含两个数组共同元素的数组,如果没有共同元素,则返回一个空(长度为0)的数组.

这是使用相交方法的相同的filteredCourses属性.

filteredCourses: function() {
  var selectedProfessors = this.get('selectedProfessors'),
      selectedLanguages = this.get('selectedLanguages'),
      selectedSubjects = this.get('selectedSubjects'),
      courses = this.get('model.courses');

  var intersectFn = Ember.EnumerableUtils.intersection;

  return courses.filter(function(course) {
    return intersectFn(course.get('professors') || [], selectedProfessors).length ||
           intersectFn(course.get('languages') || [], selectedLanguages).length ||
           intersectFn(course.get('subjects') || [], selectedSubjects).length;
  });
}.property('selectedProfessors.length', 'selectedLanguages.length', 'selectedSubjects.length')

首先,我们将交集函数别名如下：

var intersectFn = Ember.EnumerableUtils.intersection;

此步骤纯粹是简单的操作-我只是不想每次都键入Ember.EnumerableUtils.intersection；相反,我只想输入intersectFn.然后,我仅使用函数来查看数组是否相交.如果满足,则结果数组的长度将大于0,其值为true；否则为0.否则-长度为0,其值为false.所有这一切的最后一个怪癖是,有时该属性将是未定义的,从而弄乱了相交方法.对于这种情况,我将数组设置为空.

因此,course.get(‘professors’)|| []表示,如果定义了教授的属性(数组),请使用它；否则-使用一个空数组.

工作解决方案here

标签：ember-js,ember-data,javascript
来源： https://codeday.me/bug/20191028/1954713.html