const arr = [
  {
    message: 'Hello',
    messageID: 1,
  },
  {
    message: 'Hello',
    messageID: 1,
  },
  {
    message: 'World',
    messageID: 2,
  }
]

const removeDuplicates = (arr) => {
  const _obj = {}

  arr.forEach(item => {
    _obj[item.messageID] = item
  })

  return Object.values(_obj)
}

const noDuplicates = removeDuplicates(arr)
console.log(noDuplicates)

type Msg = {
  message: string,
  messageID: number
}

const arr:Msg[] = [
  {
    message: 'Hello',
    messageID: 1,
  },
  {
    message: 'Hello',
    messageID: 1,
  },
  {
    message: 'World',
    messageID: 2,
  }
]

const removeDuplicates = (arr: Msg[]) => {
  const _obj: {
    [key: number]: Msg
  } = {}

  arr.forEach(item => {
    _obj[item.messageID] = item
  })

  return Object.values(_obj)
}

const noDuplicates = removeDuplicates(arr)
console.log(noDuplicates)