Select a property from an array of objects based on a value : Javascript

You can use reduce and check if the checked property is true, then push (As pointed out by assoron) the value to the accumulator - there is no need for 2 loops:

const arr = [
  { "value": "abc", "checked": true },
  { "value": "xyz", "checked": false },
  { "value": "lmn", "checked": true }
]

const filtered = arr.reduce((a, o) => (o.checked && a.push(o.value), a), [])      
console.log(filtered)

Firstly, that's not valid JS - you need to swap your brackets and braces. Arrays use [], and objects use {}, not the other way around.

Secondly, you should first filter out the wanted objects based on the checked property, then use map to extract the properties you want:

const arr =[{"value":"abc","checked":true},{"value":"xyz","checked":false},{"value":"lmn","checked":true}];

const res = arr.filter(({ checked }) => checked).map(({ value }) => value);

console.log(res);

use filter and map:

const arr =[{"value":"abc","checked":true},{"value":"xyz","checked":false},{"value":"lmn","checked":true}];

 const result = arr.filter(res=>res.checked).map(ele=>ele.value);
 
 console.log(result);