通过相同的键组合多个数组 [英] Combine multiple arrays by same key

问题描述

我正在尝试通过特定的 key 属性组合多个数组.例如，我有

I'm trying combine multiple arrays by a specific key property. For example, I have

arr1

  [{
    key: 'A',
    items: [{name: 'a item'}]
  }, {
    key: 'B',
    items: [{name: 'b item'}]
  }]

arr2

  [{
    key: 'B',
    items: [{name: 'another b item'}, {name: 'more b items'}, {name: 'even more b items'}]
  }]

如何生成以下arr3?

  [{
    key: 'A',
    items: [{name: 'a item'}]
  },
  {
    key: 'B',
    items: [{name: 'b item'}, {name: 'another b item'}, {name: 'more b items'}, {name: 'even more b items'}]
  }]

推荐答案

可以使用这样的哈希表:

May use a hash table like this:

arr1=[{
    key: 'A',
    items: [{name: 'a item'}]
  }, {
    key: 'B',
    items: [{name: 'b item'}]
  }];

arr2=[{
    key: 'B',
    items: [{name: 'another b item'}, {name: 'more b items'}, {name: 'even more b items'}]
  }];
  
console.log(arr1.concat(arr2).reduce((function(hash){
   return function(array,obj){
    if(!hash[obj.key])
     array.push(hash[obj.key]=obj);
    else
       hash[obj.key].items.push(...obj.items);
    return array;
   };    

})({}),[]));

一些解释:

arr1.concat(arr2)//just work with one array as its easier
.reduce(...,[]));//reduce this array to the resulting array
//through
(function(hash){//an IIFE to closure our hash object
...
})({})
//which evaluates to
  function(array,obj){//take the resulting array and one object of the input
    if(!hash[obj.key])//if we dont have the key yet
     array.push(hash[obj.key]=obj);//init the object and add to our result
    else
       hash[obj.key].items.push(...obj.items);//simply concat the items
    return array;
  };    

这篇关于通过相同的键组合多个数组的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！