How to use Object.values with typescript?

I am trying to form a comma separated string from an object,

const data = {"Ticket-1.pdf":"8e6e8255-a6e9-4626-9606-4cd255055f71.pdf","Ticket-2.pdf":"106c3613-d976-4331-ab0c-d581576e7ca1.pdf"};
const values = Object.values(data).map(x => x.substr(0, x.length - 4));
const commaJoinedValues = values.join(',');
console.log(commaJoinedValues);

How to do this with TypeScript?

getting an error file:

severity: 'Error'
message: 'Property 'values' does not exist on type 'ObjectConstructor'.'
at: '216,27'
source: 'ts'

using Object.keys instead.

const data = {
  a: "first",
  b: "second",
};

const values = Object.keys(data).map(key => data[key]);

const commaJoinedValues = values.join(",");
console.log(commaJoinedValues);

Stack Overflow Q#42966362, score: 132