How to filter array of objects and get filtered object value

Question

I have an array model as below:

nodes:[
 { id: 1, label: 'label1'},
 { id: 2, label: 'label2'},
 { id: 3, label: 'label3'}
]

I whant to get the label of node filtering by id

I tried the next way, but dont get it work

const selectedNode = 2;

const nodeLabel = nodes.filter(({id}) => id.label ? id === selectedNode) // its filter here

Answer 1

There's a few ways you could do what you're trying to do. Here are a couple using native Array methods.

1. Chain filter and map and destructure the returned array.

   const [nodeLabel] = nodes
     .filter(({id}) => id === selectedNode)
     .map(({label}) => label)
   

2. Use reduce

   const nodeLabel = nodes
     .reduce((returnValue, item) => {
       if (item.id === selectedNode) return item.label
       return returnValue
     })
   

Answer 2

You were quite close.

This line

nodes.filer(({id}) => id.label ? id === selectedNode)

has few issues (assuming filer was just a typo)

• It is comparing an integer with an object. (id is the object here)

• filter will give you the list of objects rather than its property label.

• You were comparing label with id value.

• {id} to be replaced by id.

Just modify this to

nodes.filter( (id) => id.id === selectedNode )[0].label

Demo

var nodes = [
 { id: 1, label: 'label1'},
 { id: 2, label: 'label2'},
 { id: 3, label: 'label3'}
];
var selectedNode = 2;
console.log( nodes.filter( (id) => id.id === selectedNode )[0].label );

Answer 3

You can use find method by passing a callback provided function.

The find() method returns the value of the first element in the array that passed the provided testing function. Otherwise undefined is returned.

let nodes=[
 { id: 1, label: 'label1'},
 { id: 2, label: 'label2'},
 { id: 3, label: 'label3'}
];
let id=2;
let node = nodes.find(a=>a.id == id);
console.log(node ? node.label : 'id not found');

Answer 4

nodes.find(node => node.id === selectedNode).label