You can use map() method in javascript to create this structure.

Basically, you create an array with use template string then push it inside your array variable and modify it.

1 - Create an array with use your data

str = users.map(user => `@${user.id}`)

2 - Add 'ID's' text into your variable and use join() method to convert your data as a string

str = `ID\s ${str.join(', ')}`

Have a nice and productive day!

Full Code :

let users = [{
    "id": "24317318904217xxxx",
    "name": "person 1"
  },
  {
    "id": "69336408842371xxxx",
    "name": "person 2"
  }
]

str = users.map(user => `<@${user.id}>`)
str = `ID\s ${str.join(', ')}`

console.log(str)

When you are new to JS, you can get started with a simple for loop over the users array like this:

let users = [
  {"id":"24317318904217xxxx","name":"person 1"},
  {"id":"69336408842371xxxx","name":"person 2"}
]

let str = "ID's: ";

for (let i = 0; i < users.length; i++) {
    str += `<@${users[i].id}>`;
    if (i < users.length - 1)
        str += ", ";
}

To access the i-th object in the array (0-indexed) use users[i];

To access an object's 'id' property simply use object.id. Same with name and all other properties.

Read more: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object

The string concatenation might look a bit weird to you, it's a string template see: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String

The other answer uses map and join which you can read more about on the array mdn article. I highly recommend you reading into it, as Javascript code often uses these functions, but might need so getting used to for people who only ever written iterative code.

If you have any other questions feel free to ask in the comments!