@-signs in javascript object keys are tedious to work with as they can't be accessed through dot notation or unpacked using the destructuring assignment. Yet @ is used in formats like JSON-LD. This script contains two methods to recursively replace @ with $ at the start of object keys.

atToAndFrom$.js

function atTo$(data) {
  if (Array.isArray(data)) {
    return data.map(d => atTo$(d))
  } else if (typeof data === 'object' && data != null) {
    return Object.fromEntries(Object.entries(data).map(d => {
      d[0] = d[0].replace(/^@/, '$')
      return atTo$(d)
    }))
  }
  return data
}

function atFrom$(data) {
  if (Array.isArray(data)) {
    return data.map(d => atFrom$(d))
  } else if (typeof data === 'object' && data != null) {
    return Object.fromEntries(Object.entries(data).map(d => {
      d[0] = d[0].replace(/^\$/, '@')
      return atFrom$(d)
    }))
  }
  return data
}