javascript - grouping objects by properties

Question

my question is somewhat similar to javascript | Object grouping .

my input obj is

[
  {
    "name":"Display",
    "group":"Technical detals",
    "id":"60",
    "value":"4"
  },
  {
    "name":"Manufacturer",
    "group":"Manufacturer",
    "id":"58",
    "value":"Apple"
  },
  {
    "name":"OS",
    "group":"Technical detals",
    "id":"37",
    "value":"Apple iOS"
  }
]

and my required output is

 [
  {
    "name":"Display",
    "group":"Technical detals",
    "id":"60",
    "value":"4"
  },
  {
    "name":"OS",
    "group":"Technical detals",
    "id":"37",
    "value":"Apple iOS"
  },
  {
    "name":"Manufacturer",
    "group":"Manufacturer",
    "id":"58",
    "value":"Apple"
  }

]

when i tried to implement the answer ,i got

[[[object Object] {
  group: "Technical detals",
  id: "60",
  name: "Display",
  value: "4"
}, [object Object] {
  group: "Technical detals",
  id: "37",
  name: "OS",
  value: "Apple iOS"
}], [[object Object] {
  group: "Manufacturer",
  id: "58",
  name: "Manufacturer",
  value: "Apple"
}]]

i don't want to group my objects with same property into a single array . i couldn't find out where they are pushing it into array. help me to Fix it :(

Answer 1

You could group the items and the concat all groups in a single array.

It works by generating an object with the group as property an the items as items in the array.

In the next step, the object's values are taken and a new array is generated by concatination of the items with Array#reduce.

{                                                                              // hash
    "Technical detals": [
        {
            name: "Display",
            group: "Technical detals",
            id: "60",
            value: "4"
        },
        {
            name: "OS",
            group: "Technical detals",
            id: "37",
            value: "Apple iOS"
        }
    ],
    Manufacturer: [
        {
            name: "Manufacturer",
            group: "Manufacturer",
            id: "58",
            value: "Apple"
        }
    ]
}

var data = [{ name: "Display", group: "Technical detals", id: "60", value: "4" }, { name: "Manufacturer", group: "Manufacturer", id: "58", value: "Apple" }, { name: "OS", group: "Technical detals", id: "37", value: "Apple iOS" }],
    groups = Object.create(null),
    result = [];

data.forEach(function (a) {
    groups[a.group] = groups[a.group] || [];
    groups[a.group].push(a);    
});

result = Object.keys(groups).reduce(function (r, k) {
    return r.concat(groups[k]);
}, []);

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

Or just sort by group.

var data = [{ name: "Display", group: "Technical detals", id: "60", value: "4" }, { name: "Manufacturer", group: "Manufacturer", id: "58", value: "Apple" }, { name: "OS", group: "Technical detals", id: "37", value: "Apple iOS" }];

data.sort(function (a, b) {
    return a.group.localeCompare(b.group);
});

console.log(data);

.as-console-wrapper { max-height: 100% !important; top: 0; }

Answer 2

Without sorting you may group by the provided property (by) as follows;

function quasiSort(a,by){
  var h = a.reduce((h,e) => h[e[by]] ? (h[e[by]].push(e), h)
                                     : (h[e[by]] = [e], h), {});
  return Object.keys(h).reduce((r,k) => r.concat(h[k]),[]);
}
var data = [{ "name":"Display",
             "group":"Technical detals",
                "id":"60",
             "value":"4"
            },
            { "name":"Manufacturer",
             "group":"Manufacturer",
                "id":"58",
             "value":"Apple"
            },
            { "name":"OS",
             "group":"Technical detals",
                "id":"37",
             "value":"Apple iOS"
            }
           ];
           
console.log(quasiSort(data,"group"));