foam-framework/orphanage/core/KeyboardShortcutController.js

MVC metaprogramming framework

// TODO: used in saturnmail/bg.js, see if can be merged with Action keyboard support.
function KeyboardShortcutController(win, view) {
  this.contexts_ = {};
  this.body_ = {};

  this.processView_(view);

  win.addEventListener('keydown', this.processKey_.bind(this));
}

KeyboardShortcutController.prototype.processView_ = function(view) {
  var keyShortcuts = view.shortcuts;
  if (keyShortcuts) {
    keyShortcuts.forEach(function(nav) {
      var key = nav[0];
      var cb = nav[1];
      var context = nav[2];
      this.addAccelerator(key, cb, context);
    }.bind(this));
  }

  try {
    var children = view.children;
    children.forEach(this.processView_.bind(this));
  } catch(e) { console.log(e); }
};

KeyboardShortcutController.prototype.addAccelerator = function(key, callback, context) {
  if (context) {
    if (typeof(context) != 'string')
      throw "Context must be an identifier for a DOM node.";
    if (!(context in this.contexts_))
      this.contexts_[context] = {};

    this.contexts_[context][key] = callback;
  } else {
    this.body_[key] = callback;
  }
};

KeyboardShortcutController.prototype.shouldIgnoreKeyEventsForTarget_ = function(event) {
  var target = event.target;
  return target.isContentEditable || target.tagName == 'INPUT' || target.tagName == 'TEXTAREA';
};

KeyboardShortcutController.prototype.processKey_ = function(event) {
  if (this.shouldIgnoreKeyEventsForTarget_(event))
    return;

  for ( var node = event.target; node && node != document.body; node = node.parentNode ) {
    var id = node.id;
    if ( id && (id in this.contexts_) ) {
      var cbs =  this.contexts_[id];
      if ( event.keyIdentifier in cbs ) {
        var cb = cbs[event.keyIdentifier];
        cb(event);
        event.preventDefault();
        return;
      }
    }
  }
  console.log('Looking for ' + event.keyIdentifier);
  if ( event.keyIdentifier in this.body_ ) {
    var cb = this.body_[event.keyIdentifier];
    cb(event);
    event.preventDefault();
  }
};