How to get a specific index from nested array States?

Question

Hello i have a state like this;

{
  "id": "8",
  "tablename": "demo_1",
  "segments": "segment_1"
},
{
  "id": "9",
  "tablename": "demo_2",
  "segments": "segment_2"
}

I want to take segments values from tablename. Like this:

this.state.MYSTATE.map[tablename:'demo_1'];

But ofc this wont work. Any help?

use findIndex for your array like this this.state.MYSTATE.findIndex(({tablename})=>tablename=='demo_1') — Narendra Jadhav
– Narendra Jadhav, Commented Oct 22, 2018 at 11:59
or .. this.state.MYSTATE.find((x)=> x.tablename =='demo_1') OR this.state.MYSTATE.find((x)=> x.tablename =='demo_1').tablename — CodeReaper
– CodeReaper, Commented Oct 22, 2018 at 12:02
@NarendraJadhav thanks thats work :) pls write this as an answer so i can mark. — Arty
– Arty, Commented Oct 22, 2018 at 12:22

Narendra Jadhav · Accepted Answer · 2018-10-22 12:28:07Z

1

You could use .findIndex() method for array.

The findIndex() method returns the index of the first element in the array that satisfies the provided testing function. Otherwise, it returns -1, indicating no element passed the test.

DEMO

const data =[{
    "id": "8",
    "tablename": "demo_1",
    "segments": "segment_1"
  },{
    "id": "9",
    "tablename": "demo_2",
    "segments": "segment_2"
  }];
  
let index = data.findIndex(({tablename})=>tablename=='demo_1');

console.log(index);

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

answered Oct 22, 2018 at 12:28

Narendra Jadhav

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Comments

Prasanna · Accepted Answer · 2018-10-22 12:07:39Z

1

what you need is a filter followed by a map

const data = [{
  "id": "8",
  "tablename": "demo_1",
  "segments": "segment_1"
},
{
  "id": "9",
  "tablename": "demo_2",
  "segments": "segment_2"
}]

const segments = data
  .filter(item => item.tablename === 'demo_1')
  .map(item => item.segments)
  
console.log(segments)

The filter will filter all the entry with tablename equal to demo_1 and map will return the segments values of these filtered results

answered Oct 22, 2018 at 12:07

Prasanna

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