Fetch unique values from array of objects based on dynamically passed property

Question

I have this scenario where I need to fetch unique values of all objects based on a dynamically passed property . I have tried the following approach but does not seem like working.

var arr = [
  {
    id: "1",
    type: "x",
    source: {
      val1: "3",
      val2: "4",
      val3: "6",
    },
  },
  {
    id: "1",
    type: "x",
    source: {
      val1: "3",
      val2: "4",
      val3: "6",
    },
  },
  {
    id: "1",
    type: "x",
    source: {
      val1: "4",
      val2: "5",
      val3: "6",
    }
  }
];

Now say I pass val1 it should give me unique values 3,4 and if I pass val2 it should give me 4,5. P.S : I will only pass the parameter that are present inside source property.

Approach that I have tried:

 calculate = (param) =>
 {
   let uniqueValues = Array.from(
        new Set(arr.map((arr: any) => arr[param]))
   );
 }

The structure of your data will always be the same or it can be different. — Maheer Ali
– Maheer Ali, Commented Jul 4, 2019 at 12:21

Nina Scholz · Accepted Answer · 2019-07-04 12:21:30Z

2

It looks like, you need the source property as well.

new Set(arr.map((o: any) => o.source[param]))

answered Jul 4, 2019 at 12:21

Nina Scholz

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Comments

kapantzak · Accepted Answer · 2019-07-04 12:24:29Z

0

You can use map to get source values and then reduce inuque values:

const arr = [
  {
    id: "1",
    type: "x",
    source: {
      val1: "3",
      val2: "4",
      val3: "6",
    },
  },
  {
    id: "1",
    type: "x",
    source: {
      val1: "3",
      val2: "4",
      val3: "6",
    },
  },
  {
    id: "1",
    type: "x",
    source: {
      val1: "4",
      val2: "5",
      val3: "6",
    }
  }
];

function calculate(data, param) {
  return data.map(x => {
    return (x.source || {})[param];
  }).reduce((acc, val) => {
    if (acc.indexOf(val) === -1)
      acc.push(val);
    return acc;
  }, []);
}

console.log(calculate(arr, "val1"));
console.log(calculate(arr, "val2"));

answered Jul 4, 2019 at 12:24

kapantzak

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