How to get distinct properties value from array?

Question

I have this array?

var arr = [{id:"1",Name:"Tom"},
           {id:"2",Name:"Jon"},
           {id:"3",Name:"Tom"},
           {id:"4",Name:"Jack"}]

From array above I need to fecth all existing Names distinct.

var result = getNamesDistinct(arr);

The result should contain result is:

 ["Tom","Jon","Jack"];

My question is how to get all existing Names from arr distinct?

score 3 · Answer 1 · answered Dec 10 '17 at 14:02

3

If Set is available, you can simply do

new Set(arr.map(obj => obj.Name))

(pass the set to Array.from if you need an array)

answered Dec 10 '17 at 14:02

Felix Kling

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Suren Srapyan · Accepted Answer · 2017-12-11T07:48:34.093

1

You can do it via Set object

const arr = [
   { id: "1", Name: "Tom" },
   { id: "2", Name: "Jon" },
   { id: "3", Name: "Tom" },
   { id: "4", Name: "Jack" }
];

const uniqueNames = [...new Set(arr.map(item => item.Name))];

console.log(uniqueNames);

Or you can iterate over the array and add condition to get only unique names.

const arr = [
   { id: "1", Name: "Tom" },
   { id: "2", Name: "Jon" },
   { id: "3", Name: "Tom" },
   { id: "4", Name: "Jack" }
];

const uniqueNames = arr.reduce(function(arr, item) {

   if(arr.indexOf(item.Name) === -1) {
      arr.push(item.Name);
   }

   return arr;

}, []);

console.log(uniqueNames);

edited Dec 11 '17 at 07:48

answered Dec 10 '17 at 13:58

Suren Srapyan

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114
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I have syntex erroron the arrow. – Michael Dec 11 '17 at 07:36
Suren thanks for post.Can you provide example please? – Michael Dec 11 '17 at 07:44
@Michael I have updated the code – Suren Srapyan Dec 11 '17 at 07:48

score 1 · Answer 3 · edited Dec 10 '17 at 14:33

you can try this

var array = [{
        id: "1",
        Name: "Tom"
    }, {
        id: "2",
        Name: "Jon"
    }, {
        id: "3",
        Name: "Tom"
    }, {
        id: "4",
        Name: "Jack"
    }]

    function uniqueNames(array) {
        var newArray = [];
        array.forEach((value, key) => {
            newArray.push(value.Name)
        });
        return newArray
    }
   var myNewArray =  uniqueNames(array)

How to get distinct properties value from array?

3 Answers3