How to convert an array of objects into an array of objects with mapped key-value pairs

It is hard to put into words, so If anyone could help me with the title of the question, thanks in advance. At the end of the day, I have an array like so;

[ 
  {
    field: "firstname",
    value: "John"
  },
  {
    field: "lastname",
    value: "Doe"
  },
  {
    field: "hobbies",
    value: "singing, basketball"
  },
]

and the desired output will be like below;

[ 
  {
   "firstname":"John"
  },
  {
    "lastname":"Doe"
  },
  {
    "hobbies" :"singing, basketball"
  },
]

The closest question I could find similar to mine was this one: How to convert an array into an object in javascript with mapped key-value pairs?

>Solution :

let output = [ 
    {
        field: "firstname",
        value: "John"
    },
    {
        field: "lastname",
        value: "Doe"
    },
    {
        field: "hobbies",
        value: "singing, basketball"
    },
].map(a => ({[a.field]: a.value}))

console.log(output)