JavaScript：获取二维数组中某个字段的所有可能值

Question

From API I get such a json:

{
    "purposes": [
        {
            "id": 1,
            "code": "for-calls"
        },
        {
            "id": 2,
            "code": "task-management"
        },
        {
            "id": 3,
            "code": "messenger"
        }
    ],
    "availabilities": [
        {
            "id": 1,
            "code": "free"
        },
        {
            "id": 2,
            "code": "free-basic-plan"
        },
        {
            "id": 3,
            "code": "trial-version"
        }
    ],
    "ecosystems": [
        {
            "id": 1,
            "code": "browse-widget"
        },
        {
            "id": 2,
            "code": "web-app"
        },
        {
            "id": 3,
            "code": "installation-on-your-server"
        }
    ]
}

How do I iterate over this json to get a new array containing the field values 'code' from each element. As a result, there should be /catalog/filter/value_of_code in each element of the array.

Answer 1

const obj = {
  "purposes": [
    {
      "id": 1,
      "code": "for-calls"
    },
    {
      "id": 2,
      "code": "task-management"
    },
    {
      "id": 3,
      "code": "messenger"
    }
  ],
  "availabilities": [
    {
      "id": 1,
      "code": "free"
    },
    {
      "id": 2,
      "code": "free-basic-plan"
    },
    {
      "id": 3,
      "code": "trial-version"
    }
  ],
  "ecosystems": [
    {
      "id": 1,
      "code": "browse-widget"
    },
    {
      "id": 2,
      "code": "web-app"
    },
    {
      "id": 3,
      "code": "installation-on-your-server"
    }
  ]
}

const arr = Object.values(obj).reduce((acc, e) => [...acc, ...e.map(o => `/catalog/filter/${o.code}`)] ,[]);

console.log( arr );

Answer 2

Lets say you are receiving this JSON object in serverResp object. Now lets check if any catalogs are present in the object.

if(Object.keys(serverResp).length)

Next we shall iterate over the catalogs

Object.keys(serverResp).forEach((cat) => )

Each cat represents a catalog. Next we shall fetch array against each key inside our forloop

const catItems = serverResp[cat];

catItems will contain all the items of a particular catalog. Now lets iterate over each catItems to get the "code" value

catItems.forEach(item => console.log(item.code));

Final piece of code will look like below-

const outputArray = [];
if(Object.keys(serverResp).length) {
    Object.keys(serverResp).forEach((cat)=> {
    const catItems = serverResp[cat];
    catItems.forEach(item => 
    outputArray.push(`/catalog/filter${item.code}`));
  });
 }

 console.log(outputArray);