.put()

gun.put(data)
gun.put(data, callback)
gun.put(data, callback, options)

// Write a simple object
gun.get('user/alice').put({
  name: 'Alice',
  age: 30,
  city: 'Portland'
})

// Nested writes are automatically handled
gun.get('alice').put({
  profile: {
    bio: 'Software developer',
    avatar: 'https://example.com/avatar.jpg'
  }
})

// Update a single property
gun.get('user/alice').get('name').put('Alice Smith')

// Update multiple properties
gun.get('user/alice').put({
  name: 'Alice Smith',
  updatedAt: Date.now()
})

gun.get('user/alice').put({
  name: 'Alice',
  email: 'alice@example.com'
}, function(ack){
  if(ack.err){
    console.error('Write failed:', ack.err)
  } else {
    console.log('Write successful!')
  }
})

// Fetch data asynchronously before writing
gun.get('weather').put(function(callback){
  fetch('https://api.weather.com/current')
    .then(res => res.json())
    .then(data => callback({
      temp: data.temperature,
      conditions: data.conditions,
      timestamp: Date.now()
    }))
})

// Set a property to null to delete it
gun.get('user/alice').get('email').put(null)

// Or in an object
gun.get('user/alice').put({
  email: null,  // Deletes the email property
  phone: null   // Deletes the phone property
})

// Link to another node
var alice = gun.get('user/alice')
var car = gun.get('car/toyota123')

alice.get('car').put(car)

// Later, traverse the relationship
alice.get('car').once(function(carData){
  console.log('Alice\'s car:', carData)
})

Gun.chain.put = function(data, cb, as){
  var gun = this, at = gun._, root = at.root;
  as = as || {};
  as.root = at.root;
  as.run || (as.run = root.once);
  stun(as, at.id); // set a flag for reads to check if this chain is writing
  as.ack = as.ack || cb;
  as.via = as.via || gun;
  as.data = as.data || data;
  as.soul || (as.soul = at.soul || ('string' == typeof cb && cb));
  var s = as.state = as.state || Gun.state();
  // ... graph walking and state resolution
}

// Both peers write simultaneously
// Peer 1:
gun.get('doc').put({ text: 'Hello' })

// Peer 2:
gun.get('doc').put({ text: 'World' })

// GUN automatically resolves: the write with the
// higher timestamp wins (last-write-wins)

// These will cause errors:
gun.get('data').put(undefined)        // Invalid
gun.get('data').put([1, 2, 3])       // Use .set() instead
gun.get('data').put(Infinity)        // Invalid number
gun.get('data').put(new Date())      // Use Date.now() instead