如何使用 lodash 在数组中查找具有值的对象答案

【问题标题】：How to find object with value in array using lodash如何使用 lodash 在数组中查找具有值的对象
【发布时间】：2016-07-10 05:06:03
【问题描述】：

给出如下JS数组：

vm.todayShifts = [];
vm.todayShifts['am'] = 
    {
      station: "1",
      slots: {
        position: "AO", 
        name: "Person One"
      },
      slots: {
        position: "FF", 
        name: "Person Two"
      },
      slots: {
        position: "PFF", 
        name: "Person Three"
      },
    },
    {
      station: "2",
      slots: {
        position: "AO", 
        name: "Person Four"
      },
      slots: {
        position: "FF", 
        name: "Person Fve"
      },
      slots: {
        position: "PFF", 
        name: "Person Six"
      },
    },
  ],
todayShifts['pm'] = 
    {
      station: "1",
      slots: {
        position: "AO", 
        name: "Person Seven"
      },
      {
        position: "FF", 
        name: "Person Eight"
      },
      {
        position: "PFF", 
        name: "Person Nine"
      },
    },
    {
      station: "2",
      slots: {
        position: "AO", 
        name: "Person Ten"
      },
      {
        position: "FF", 
        name: "Person Eleven"
      },
      {
        position: "PFF", 
        name: "Person Twelve"
      },
    },
  ]

在循环中的某一时刻，我有 station.id 和 dayPart（am 或 pm）值，我需要查看 todayShift 数组是否包含位于适当 dayPart 中且具有 station.id 值的对象，如果存在则返回该对象。我已经用 lodash 试过了：

      if (typeof vm.todayShifts[dayPart] != 'undefined') {
        var shift = _.find(vm.todayShifts[dayPart], {'station': station.id});
      }

但即使存在符合条件的数据（例如 dayPart="am" 和 station = 1），也不会返回任何内容。

这已经在一个循环中（在 cell modifier 中，对于带有 Angular Bootstrap 日历的 custom cell template），所以我不想每次都循环遍历 todayShifts，因为这个控制器会每页被调用约 30 次。

我接近了吗？还是有更简单的方法来检查和获取该对象？

谢谢。

【问题讨论】：

如果您将 todayShifts 视为一个对象，为什么它是一个数组。我知道 javascript 允许你做这样奇怪的事情，但是为什么......

标签： javascript arrays object lodash

【解决方案1】：

改用函数

var shift = _.find(vm.todayShifts[dayPart], function(shift){ return shift.station ==  station.id });

【讨论】：

【解决方案2】：

查看控制台查看结果。

vm = Object;
vm.todayShifts = [];
vm.todayShifts['am'] = [
    {
      station: "1",
      slots: [{
	        position: "AO", 
	        name: "Person One"
	      },
	      {
	        position: "FF", 
	        name: "Person Two"
	      },
	     {
	        position: "PFF", 
	        name: "Person Three"
	      }]
    },
    {
      station: "2",
      slots: [{
	        position: "AO", 
	        name: "Person Four"
	      },
	      {
	        position: "FF", 
	        name: "Person Fve"
	      },
	      {
	        position: "PFF", 
	        name: "Person Six"
	      }]
    },
  ],
vm.todayShifts['pm'] = [
    {
      station: "1",
      slots: [{
	        position: "AO", 
	        name: "Person Seven"
	      },
	      {
	        position: "FF", 
	        name: "Person Eight"
	      },
	      {
	        position: "PFF", 
	        name: "Person Nine"
	      }]
    },
    {
      station: "2",
      slots: [{
	        position: "AO", 
	        name: "Person Ten"
	      },
	      {
	        position: "FF", 
	        name: "Person Eleven"
	      },
	      {
	        position: "PFF", 
	        name: "Person Twelve"
	      }]
    }
   
  ]
  
  function getShift(dayPart, stationId){
    if (typeof vm.todayShifts[dayPart] != 'undefined') {
          var shift = _.filter(vm.todayShifts[dayPart], {'station': stationId});
          return shift;
       }
        
  }
  var ob = getShift("pm", "2");
  
  console.log(ob);

&lt;script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore-min.js"&gt;&lt;/script&gt;

【讨论】：