Grouping based on unique key in array of object

问题

I am working on a small React project where I am stuck at this point. I need to make a grouping based on array object key.

Below is the Array:

   let addOnFeatures = [
    {"name": "feature1", id: 101, cost: 100},
    {"name": "feature2", id: 102, cost: 200},
    {"name": "feature1", id: 103, cost: 300},
    {"name": "feature3", id: 104, cost: 40}
    ]

I need to make a grouping based on name key so that every id related to common name should be displayed on its own tab.

Expected output should be like

*uniqueFeaturename
id: cost

Example:

 1. feature1
   101 : 100
   103 : 300
 2. feature2
    102 : 200
 3. feature3
    104: 40

回答1:

Just make use of Array.prototype.reduce and add elements to object like

let addOnFeatures = [
    {"name": "feature1", id: 101, cost: 100},
    {"name": "feature2", id: 102, cost: 200},
    {"name": "feature1", id: 103, cost: 300},
    {"name": "feature3", id: 104, cost: 40}
]

const res = addOnFeatures.reduce((acc, item) => {
   if(acc[item.name]) {
      acc[item.name] = {...acc[item.name], [item.id]: item.cost};
   } else {
      acc[item.name] = {[item.id]: item.cost};
   }
   return acc;
}, {});

console.log(res);

回答2:

One solution can be this:

 let addOnFeatures = [
    {"name": "feature1", id: 101, cost: 100},
    {"name": "feature2", id: 102, cost: 200},
    {"name": "feature1", id: 103, cost: 300},
    {"name": "feature3", id: 104, cost: 40}
    ];
    
    var res={}; 
    addOnFeatures.forEach(i=>{
    
       if(!res[i.name]){
         res[i.name] = [{id: i.id, cost:i.cost}]
       }else{
        res[i.name].push({id: i.id, cost:i.cost})
       }
    }
    );
    
    console.log(res)

Or this

 let addOnFeatures = [
    {"name": "feature1", id: 101, cost: 100},
    {"name": "feature2", id: 102, cost: 200},
    {"name": "feature1", id: 103, cost: 300},
    {"name": "feature3", id: 104, cost: 40}
    ];
    
   var res2={}; 
    addOnFeatures.forEach(i=>{
        res2[i.name] = res2[i.name] ? [...res2[i.name],...[{id: i.id, cost:i.cost}]] :[...[{id: i.id, cost:i.cost}]]
    }
    );
    
    console.log(res2)

来源：https://stackoverflow.com/questions/62058409/grouping-based-on-unique-key-in-array-of-object

标签

javascript

reactjs

ecmascript-6