Store data in Local Storage from JSON file

I am trying to store data in the local Storage from my JSON file. But I am getting an empty array in the local Storage. File name is 'data' in the project.
"friends": (
"id": 0,
"name": "Daugherty Gould"
"id": 1,
"name": "Foley Carpenter"
"id": 2,
"name": "Brewer Vinson"

localStorage.setItem('firstName', );

I am not getting the right output with above code. How can I get all the names in localstorage.

Thank you in advance!