How to modify an object regarless of inexistence value

I'm currently learning Graphql and I'm messing around with it,

I've this mutation resolver where links is just an array of objects links = [{ ... }]

Mutation : {
   update(parent, args) => {
      links[args.id] = {
         description: args.description,
         url: args.url,
      }
   }
}

In this current configuration if i update the id=0 which contains the following:

{
   id: 0,
   description: "test",
   url: "www.test.com",
}

The problem would be that if in the argsparameter there is no description, then its value would be wiped out:

mutation {
  update(id:0, url:"hello.com") {
    url
  }
}

results in

{
   id: 0,
   url: "hello.com"
}

Desired Behavior would be that if one of the two fields is not declared that would not affect its current value

What i tried:

Mutation : {
   update(parent, args) => {
      links[args.id] = {
         description: (!!args.description ? void(0) : args.description ), // Check if description is null; if so, do nothing, else update the value
         url: args.url,
      }
   }
}

I've to clarify that, assigning undefined to description is not what i want, I'm looking for a way to implement this using a inline if, and avoid idempotency, to keep things clean, i don't want something like this:

if (!!args.description)
   ...
else
   ...

Use the spread operator:

<!-- begin snippet: js hide: false console: true babel: false -->

<!-- language: lang-js -->

const links = [{
   id: 0,
   description: "test",
   url: "www.test.com",
}]

function update({id, ...args}) {
  links[id] = { ...links[id], ...args }
}

update({id: 0, url: 'www.wikipedia.org'})

console.log(links)

<!-- end snippet -->