ReactJS/JavaScript find array in object

Question

I have a string value and an object obj, want to convert value to array then find it in obj by value, and get name but it return undefined, what I have missed?

let value = '3,4';
let obj = {
  "DistrictData": [{
    "id": 3,
    "name": 'blah'
  }, {
    "id": 4,
    "name": 'oops'
  }]
}

let res = value.split(',').map((v, i) => obj.DistrictData.find(o => o.id === v))
console.log(res)

=== compares both the type and the value, and you're comparing a string and a number which means o.id === v will never be true, try using just ==. — Titus
– Titus, Commented Feb 9, 2020 at 21:01

Nina Scholz · Accepted Answer · 2020-02-09 21:01:57Z

3

You need to find with a number value, because split returns an array of strings. Then map the name as well.

let value = '3,4',
    obj = { DistrictData: [{ id: 3, name: 'blah' }, { id: 4, name: 'oops' }] },
    res = value
        .split(',')
        .map((v, i) => obj.DistrictData.find(o => o.id === +v))
        .map(o => o.name);

console.log(res);

answered Feb 9, 2020 at 21:01

Nina Scholz

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Comments

faruk · Accepted Answer · 2020-02-09 21:21:12Z

1

you can normalize array

to like

  let obj = { "DistrictData": {"3":{ "id": 3,"name": 'blah'}, "4":{"id": 4,"name": 'oops'}}

then you can filter on name

normalizr

answered Feb 9, 2020 at 21:21

faruk

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Comments

Pranav C Balan · Accepted Answer · 2020-02-10 06:56:20Z

1

The split array contains string value and within find you are comparing string with number so either convert string to number or use == to ignore checking type. And finally get the name property from the object.

let value = '3,4';
let obj = {
  "DistrictData": [{
    "id": 3,
    "name": 'blah'
  }, {
    "id": 4,
    "name": 'oops'
  }]
}

let res = value.split(',').map((v, i) => (bj.DistrictData.find(o => o.id == v).name)
console.log(res)

Refer : Which equals operator (== vs ===) should be used in JavaScript comparisons?

edited Feb 10, 2020 at 6:56

answered Feb 9, 2020 at 21:03

Pranav C Balan

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