如何查找数组中另一个对象旁边的对象

How to find the object that's next to another object in an array?

本文关键字：一个对象 对象 数组 何查找 查找      更新时间：2023-09-26

假设我有一个数组内的objectA：[ { name: 'ObjectA'}, { name: 'ObjectB'}, { name: 'ObjectC' } ]

如何找到ObjectA旁边的对象（例如 ObjectB ）？

（我可以使用vanilla JavaScript或Lodash。

您可以使用Array.prototype.reduce()： 

var arr = [{
  name: 'ObjectA'
}, {
  name: 'ObjectB'
}, {
  name: 'ObjectC'
}];
var nxt = arr.reduce(function(a, b){
   return (a.name === 'ObjectA') ? b : a;
});
document.querySelector('pre').innerHTML = JSON.stringify(nxt, 0 , 4);
<pre></pre>

假设你想要下一个对象，给定当前对象的名称，试试这个。 

var getNextObject = function(arr,name){
  var currIndex = - 1;
  arr.forEach((i,index)=>{
    if(i.name === name){
      currIndex = index;
    };
  });
  if(currIndex < (arr.length - 1 && currIndex >=0)){
      return arr[currIndex+1];
    }
  //return null if its the last element or the object with such name does not exist in the array
  return null;
}
var arr = [ { name: 'ObjectA'}, { name: 'ObjectB'}, { name: 'ObjectC' } ];
//Most of the code from here on is for demonstration purposes
//
// This function call is good enough ==>  getNextObject(arr,'ObjectA');
// 
var nextOfObjectA = getNextObject(arr,'ObjectA');
var myprea = document.getElementById('newprea');
if(nextOfObjectA && nextOfObjectA.name){
   myprea.innerHTML = nextOfObjectA.name;
}else{
    myprea.innerHTML = 'does not exist';
}
var nextOfObjectC = getNextObject(arr,'ObjectC');
var myprec = document.getElementById('newprec');
//Object C is the last element, hence the function returns null
if(nextOfObjectC && nextOfObjectC.name){
   myprec.innerHTML = nextOfObjectC.name;
}else{
    myprec.innerHTML = 'does not exist';
}
<br/>
<p> Next Object for objectA = <span id="newprea"></span> </p>
<br/>
<p> Next Object for objectC = <span id="newprec"></span> </p>

你可以找到对象的索引（使用 findIndex），然后获取下一项。

var objArr = [ { name: 'ObjectA'}, { name: 'ObjectB'}, { name: 'ObjectC' } ];
var nextObj = objArr[objArr.findIndex(function(item, index) { return item.name == this;}, 'ObjectA')+1];
alert(JSON.stringify(nextObj));
console.log(nextObj);

试试这个

var arr = [ { name: 'ObjectA'}, { name: 'ObjectB'}, { name: 'ObjectC' } ];
var objIndex = -1;
arr.forEach( function(value, index){ if ( value.name == "ObjectA" ){ objIndex = index + 1; } } );
console.log( arr[objIndex].name );

试试这个：

function getNextOrDefault (name){
//Fetch index of item.
var index = _.findIndex(ary,function(item){  
                             return item.name === name; 
                             });
 //If item found (!==-1) and has next  item (item's index + 1 > length of array)
 return (index !== -1 ? index++ : index) > ary.length || index === -1 
        //Return default
        ? null 
        //Return next item
        : ary[index] ;
}

小提琴：https://jsfiddle.net/k4dgnzpf/

希望这有帮助！

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