neo-blessed/lib/events.js

/**
 * events.js - event emitter for blessed
 * Copyright (c) 2013-2015, Christopher Jeffrey and contributors (MIT License).
 * https://github.com/chjj/blessed
 */

var slice = Array.prototype.slice;

/**
 * EventEmitter
 */

function EventEmitter() {
  if (!this._events) this._events = {};
}

EventEmitter.prototype.setMaxListeners = function(n) {
  this._maxListeners = n;
};

EventEmitter.prototype.addListener = function(type, listener) {
  if (!this._events[type]) {
    this._events[type] = listener;
  } else if (typeof this._events[type] === 'function') {
    this._events[type] = [this._events[type], listener];
  } else {
    this._events[type].push(listener);
  }
  this._emit('newListener', [type, listener]);
};

EventEmitter.prototype.on = EventEmitter.prototype.addListener;

EventEmitter.prototype.removeListener = function(type, listener) {
  var handler = this._events[type];
  if (!handler) return;

  if (typeof handler === 'function' || handler.length === 1) {
    delete this._events[type];
    this._emit('removeListener', [type, listener]);
    return;
  }

  for (var i = 0; i < handler.length; i++) {
    if (handler[i] === listener || handler[i].listener === listener) {
      handler.splice(i, 1);
      this._emit('removeListener', [type, listener]);
      return;
    }
  }
};

EventEmitter.prototype.off = EventEmitter.prototype.removeListener;

EventEmitter.prototype.removeAllListeners = function(type) {
  if (type) {
    delete this._events[type];
  } else {
    this._events = {};
  }
};

EventEmitter.prototype.once = function(type, listener) {
  function on() {
    this.removeListener(type, on);
    return listener.apply(this, arguments);
  }
  on.listener = listener;
  return this.on(type, on);
};

EventEmitter.prototype.listeners = function(type) {
  return typeof this._events[type] === 'function'
    ? [this._events[type]]
    : this._events[type] || [];
};

EventEmitter.prototype._emit = function(type, args) {
  var handler = this._events[type]
    , ret;

  if (!handler) {
    if (type === 'error') {
      throw new args[0];
    }
    return;
  }

  if (typeof handler === 'function') {
    return handler.apply(this, args);
  }

  for (var i = 0; i < handler.length; i++) {
    if (handler[i].apply(this, args) === false) {
      ret = false;
    }
  }

  return ret !== false;
};

EventEmitter.prototype.emit = function(type) {
  var args = slice.call(arguments, 1)
    , el = this;

  if (this.type === 'screen') {
    return this._emit(type, args);
  }

  if (this._emit(type, args) === false) {
    return false;
  }

  type = 'element ' + type;
  args.unshift(this);

  do {
    if (!el._events[type]) continue;
    if (el._emit(type, args) === false) {
      return false;
    }
  } while (el = el.parent);

  return true;
};

// For hooking into the main EventEmitter if we want to.
// Might be better to do things this way being that it
// will always be compatible with node, not to mention
// it gives us domain support as well.
// Node.prototype._emit = Node.prototype.emit;
// Node.prototype.emit = function(type) {
//   var args, el;
//
//   if (this.type === 'screen') {
//     return this._emit.apply(this, arguments);
//   }
//
//   this._emit.apply(this, arguments);
//   if (this._bubbleStopped) return false;
//
//   args = slice.call(arguments, 1);
//   el = this;
//
//   args.unshift('element ' + type, this);
//   this._bubbleStopped = false;
//   //args.push(stopBubble);
//
//   do {
//     if (!el._events || !el._events[type]) continue;
//     el._emit.apply(el, args);
//     if (this._bubbleStopped) return false;
//   } while (el = el.parent);
//
//   return true;
// };
//
// Node.prototype._addListener = Node.prototype.addListener;
// Node.prototype.on =
// Node.prototype.addListener = function(type, listener) {
//   function on() {
//     if (listener.apply(this, arguments) === false) {
//       this._bubbleStopped = true;
//     }
//   }
//   on.listener = listener;
//   return this._addListener(type, on);
// };

/**
 * Expose
 */

exports = EventEmitter;
exports.EventEmitter = EventEmitter;

module.exports = exports;