.set()

gun.set(item)
gun.set(item, callback)
gun.set(item, callback, options)

// Create a todo list
var todos = gun.get('todos')

todos.set({
  text: 'Buy groceries',
  done: false,
  created: Date.now()
})

todos.set({
  text: 'Walk the dog',
  done: false,
  created: Date.now()
})

gun.get('messages').set({
  from: 'alice',
  text: 'Hello!',
  timestamp: Date.now()
}, function(ack){
  if(ack.err){
    console.error('Failed to add message:', ack.err)
  } else {
    console.log('Message added successfully')
  }
})

// Create a user
var alice = gun.get('user/alice').put({
  name: 'Alice',
  email: 'alice@example.com'
})

// Add to a collection
gun.get('users').set(alice)

// Now alice is in the users set
gun.get('users').map().once(function(user){
  console.log('User:', user.name)
})

var chat = gun.get('chat/room1')
var messages = chat.get('messages')

// Send message function
function sendMessage(text, from) {
  messages.set({
    text: text,
    from: from,
    timestamp: Date.now()
  })
}

// Listen for new messages
messages.map().on(function(msg){
  displayMessage(msg)
})

sendMessage('Hello everyone!', 'alice')
sendMessage('Hi Alice!', 'bob')

var feed = gun.get('feed/alice')

// Add a post
feed.set({
  type: 'post',
  content: 'Just deployed my app!',
  timestamp: Date.now(),
  likes: 0
})

// Add a photo
feed.set({
  type: 'photo',
  url: 'https://example.com/photo.jpg',
  caption: 'Beautiful sunset',
  timestamp: Date.now()
})

// Display the feed
feed.map().on(function(item){
  if(item.type === 'post'){
    showPost(item)
  } else if(item.type === 'photo'){
    showPhoto(item)
  }
})

// .set() returns reference to the new item
var newTodo = gun.get('todos').set({
  text: 'New task',
  done: false
})

// You can immediately chain operations on it
newTodo.once(function(data){
  console.log('Todo ID:', this._.get)
  console.log('Todo data:', data)
})

// Update the item later
newTodo.get('done').put(true)

Gun.chain.set = function(item, cb, opt){
  var gun = this, root = gun.back(-1), soul, tmp;
  cb = cb || function(){};
  opt = opt || {}; opt.item = opt.item || item;
  if(soul = ((item||'')._||'')['#']){ (item = {})['#'] = soul }
  if('string' == typeof (tmp = Gun.valid(item))){
    return gun.get(soul = tmp).put(item, cb, opt)
  }
  if(!Gun.is(item)){
    if(Object.plain(item)){
      item = root.get(soul = gun.back('opt.uuid')()).put(item);
    }
    return gun.get(soul || root.back('opt.uuid')(7)).put(item, cb, opt);
  }
  gun.put(function(go){
    item.get(function(soul, o, msg){
      if(!soul){ return cb.call(gun, {err: Gun.log('Only a node can be linked!')}) }
      (tmp = {})[soul] = {'#': soul}; go(tmp);
    },true);
  })
  return item;
}

gun.get('items').set({ value: 'A' })  // ID: abc123xyz
gun.get('items').set({ value: 'B' })  // ID: def456uvw
gun.get('items').set({ value: 'C' })  // ID: ghi789rst

// Access by ID if you know it
gun.get('items').get('abc123xyz').once(function(data){
  console.log(data)  // { value: 'A' }
})

// Add items
var set = gun.get('mySet')
set.set('item1')
set.set('item2')
set.set('item3')

// Iterate all items
set.map().once(function(item){
  console.log('Item:', item)
})

// You cannot remove from a set directly
// Instead, mark items as deleted:
set.map().once(function(item, key){
  gun.get('mySet').get(key).put(null)  // "Delete" the item
})

// ❌ Cannot add primitive values directly
gun.get('list').set('hello')  // Will create a node containing 'hello'

// ❌ No built-in duplicate prevention
gun.get('list').set({ value: 'A' })
gun.get('list').set({ value: 'A' })  // Both are added as separate items

// ❌ No guaranteed order
gun.get('list').set({ order: 1 })
gun.get('list').set({ order: 2 })
// Items may appear in any order when iterating

// ✅ For ordered lists, add order property
gun.get('list').set({ 
  value: 'item',
  order: Date.now()  // Use timestamp for order
})