demo.js

Missive.on('change:conversations', (ids) => {
  Missive.fetchConversation(ids, ['authors','latest_message']).then((conversations) => {
    if (conversations.length != 1) {
      // Do nothing if multiple conversations are selected.
      return
    }
 
    let addressFields = Missive.getEmailAddresses(conversations[0])

    for (let addressField of addressFields) {
      let { address, name } = addressField
      console.log(name, address)
      // Code could ignore your own business domain name
      // Code could query your backend & update the iframe content
    }
  })
})