get values in an array inside an array

Question

I have a question here I want to get all the value of the values array inside this array.

const sample = [
  {
    "key": "sampleKey", "values":
      [
        { "key": "insidesampleKey", "value": 2 },
        { "key": "insideofinside", "value": 2 }
      ]
  },

  { 
    "key": "sampleKey2", "values": 
      [
        { "key": "insideSampleKey2", "value": 1 }
      ] 
  },

  { 
    "key": "samplkey3", "values": 
      [
        { "key": "insideofsampleKey3", "value": 1 }
      ] 
  }
]

So far, I can only print the first one console.log(sample[0].values[0].value). I appreciate with any helps. Thanks much and have a great weekend

user10931450 · Accepted Answer · 2019-01-18 04:11:42Z

1

I think flatMap may be the best way to deal with this.

sample.flatMap(outer => outer.values.map(inner => inner.value))

answered Jan 18, 2019 at 4:11

user10931450

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JohanP · Accepted Answer · 2019-01-18 03:58:40Z

1

You can use reduce and concat to get a flat, single array.

const sample = [{"key":"sampleKey","values":
  [{"key":"insidesampleKey","value":2},{"key":"insideofinside","value":2}]},

{"key":"sampleKey2","values":[{"key":"insideSampleKey2","value":1}]},

{"key":"samplkey3","values":[{"key":"insideofsampleKey3","value":1}]}]

var values = sample.reduce((acc, item) => acc.concat(item.values.map(v=> v.value)),[]);
console.log(values);

answered Jan 18, 2019 at 3:58

JohanP

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Comments

Dhananjai Pai · Accepted Answer · 2019-01-18 03:57:18Z

0

The easiest method is to use a flatMap over the array as below. You can use polyfill for browsers that don't support the same yet. Use MDN to learn more.

sample.flatMap(item => item.values.map(inner => inner.value))

answered Jan 18, 2019 at 3:57

Dhananjai Pai

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Jack Bashford · Accepted Answer · 2019-01-18 04:00:44Z

0

If you want to print the other value properties, just map over the array, then look at the values array, then look at value, and finally use flat to get a single array:

const sample = [{
    "key": "sampleKey",
    "values": [{
      "key": "insidesampleKey",
      "value": 2
    }, {
      "key": "insideofinside",
      "value": 2
    }]
  },

  {
    "key": "sampleKey2",
    "values": [{
      "key": "insideSampleKey2",
      "value": 1
    }]
  },

  {
    "key": "samplkey3",
    "values": [{
      "key": "insideofsampleKey3",
      "value": 1
    }]
  }
];

console.log(sample.map(e => e.values.map(x => x.value)).flat(1));

answered Jan 18, 2019 at 4:00

Jack Bashford

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