How to fetch matching key values from JSON object?

Question

I have an object with the following data:

obj =
{
  key: 'mykey1597855209',
  integrity: 'sha512-T9JW=='
}
{
  key: 'mykey159785520915978552101597855212',
  integrity: 'sha512-T9JWj=='
}
{
  key: 'mykey15978552091597855210',
  integrity: 'sha512-lcddfd=='
}
{
  key: 'otherkey15978552091597855210',
  integrity: 'sha512-abcdfd=='
}

When I do console.log(typeof obj) , I get object as output

I want to store only unique integrity values in an array for the keys which have mykey* in the key value

Desired Output:

[ 'sha512-T9JWj==', 'sha512-lcddfd==' ]

Code:

var output = [];

for (var key in obj) {
  if(obj[key] === 'mykey') {
    output.push(obj[integrity])
  }
}

console.log(output.join(', '))

Answer 1

You first filter the array to obtain only objects with a matching key value, map each resulting element to its integrity property, create a Set from that array, and finally use spread syntax to obtain the result as an array.

 const arr = [ { key: 'mykey1597855209', integrity: 'sha512-T9JWj==' }, { key: 'mykey159785520915978552101597855212', integrity: 'sha512-T9JWj==' }, { key: 'mykey15978552091597855210', integrity: 'sha512-lcddfd==' }, { key: 'otherkey15978552091597855210', integrity: 'sha512-abcdfd==' }]; const res = [...new Set(arr.filter(({key})=>/mykey/.test(key)).map(({integrity})=>integrity))]; console.log(res);