basant307/AI_Governance_Project

1import * as util from './util/index.mjs';2import * as is from './is.mjs';3import Event from './event.mjs';4 5const eventRegex = /^([^.]+)(\.(?:[^.]+))?$/; // regex for matching event strings (e.g. "click.namespace")6const universalNamespace = '.*'; // matches as if no namespace specified and prevents users from unbinding accidentally7 8const defaults = {9  qualifierCompare: function( q1, q2 ){10    return q1 === q2;11  },12  eventMatches: function( /*context, listener, eventObj*/ ){13    return true;14  },15  addEventFields: function( /*context, evt*/ ){16  },17  callbackContext: function( context/*, listener, eventObj*/ ){18    return context;19  },20  beforeEmit: function(/* context, listener, eventObj */){21  },22  afterEmit: function(/* context, listener, eventObj */){23  },24  bubble: function( /*context*/ ){25    return false;26  },27  parent: function( /*context*/ ){28    return null;29  },30  context: null31};32 33let defaultsKeys = Object.keys( defaults );34let emptyOpts = {};35 36function Emitter( opts = emptyOpts, context ){37  // micro-optimisation vs Object.assign() -- reduces Element instantiation time38  for( let i = 0; i < defaultsKeys.length; i++ ){39    let key = defaultsKeys[i];40 41    this[key] = opts[key] || defaults[key];42  }43 44  this.context = context || this.context;45  this.listeners = [];46  this.emitting = 0;47}48 49let p = Emitter.prototype;50 51let forEachEvent = function( self, handler, events, qualifier, callback, conf, confOverrides ){52  if( is.fn( qualifier ) ){53    callback = qualifier;54    qualifier = null;55  }56 57  if( confOverrides ){58    if( conf == null ){59      conf = confOverrides;60    } else {61      conf = util.assign( {}, conf, confOverrides );62    }63  }64 65  let eventList = is.array(events) ? events : events.split(/\s+/);66 67  for( let i = 0; i < eventList.length; i++ ){68    let evt = eventList[i];69 70    if( is.emptyString( evt ) ){ continue; }71 72    let match = evt.match( eventRegex ); // type[.namespace]73 74    if( match ){75      let type = match[1];76      let namespace = match[2] ? match[2] : null;77      let ret = handler( self, evt, type, namespace, qualifier, callback, conf );78 79      if( ret === false ){ break; } // allow exiting early80    }81  }82};83 84let makeEventObj = function( self, obj ){85  self.addEventFields( self.context, obj );86 87  return new Event( obj.type, obj );88};89 90let forEachEventObj = function( self, handler, events ){91  if( is.event( events ) ){92    handler( self, events );93 94    return;95  } else if( is.plainObject( events ) ){96    handler( self, makeEventObj( self, events ) );97 98    return;99  }100 101  let eventList = is.array(events) ? events : events.split(/\s+/);102 103  for( let i = 0; i < eventList.length; i++ ){104    let evt = eventList[i];105 106    if( is.emptyString( evt ) ){ continue; }107 108    let match = evt.match( eventRegex ); // type[.namespace]109 110    if( match ){111      let type = match[1];112      let namespace = match[2] ? match[2] : null;113      let eventObj = makeEventObj( self, {114        type: type,115        namespace: namespace,116        target: self.context117      } );118 119      handler( self, eventObj );120    }121  }122};123 124p.on = p.addListener = function( events, qualifier, callback, conf, confOverrides ){125  forEachEvent( this, function( self, event, type, namespace, qualifier, callback, conf ){126    if( is.fn( callback ) ){127      self.listeners.push( {128        event: event, // full event string129        callback: callback, // callback to run130        type: type, // the event type (e.g. 'click')131        namespace: namespace, // the event namespace (e.g. ".foo")132        qualifier: qualifier, // a restriction on whether to match this emitter133        conf: conf // additional configuration134      } );135    }136  }, events, qualifier, callback, conf, confOverrides );137 138  return this;139};140 141p.one = function( events, qualifier, callback, conf ){142  return this.on( events, qualifier, callback, conf, { one: true } );143};144 145p.removeListener = p.off = function( events, qualifier, callback, conf ){146  if( this.emitting !== 0 ){147    this.listeners = util.copyArray( this.listeners );148  }149 150  let listeners = this.listeners;151 152  for( let i = listeners.length - 1; i >= 0; i-- ){153    let listener = listeners[i];154 155    forEachEvent( this, function( self, event, type, namespace, qualifier, callback/*, conf*/ ){156      if(157        ( listener.type === type || events === '*' ) &&158        ( (!namespace && listener.namespace !== '.*') || listener.namespace === namespace ) &&159        ( !qualifier || self.qualifierCompare( listener.qualifier, qualifier ) ) &&160        ( !callback || listener.callback === callback )161      ){162        listeners.splice( i, 1 );163 164        return false;165      }166    }, events, qualifier, callback, conf );167  }168 169  return this;170};171 172p.removeAllListeners = function(){173  return this.removeListener('*');174};175 176p.emit = p.trigger = function( events, extraParams, manualCallback ){177  let listeners = this.listeners;178  let numListenersBeforeEmit = listeners.length;179 180  this.emitting++;181 182  if( !is.array( extraParams ) ){183    extraParams = [ extraParams ];184  }185 186  forEachEventObj( this, function( self, eventObj ){187    if( manualCallback != null ){188      listeners = [{189        event: eventObj.event,190        type: eventObj.type,191        namespace: eventObj.namespace,192        callback: manualCallback193      }];194 195      numListenersBeforeEmit = listeners.length;196    }197 198    for( let i = 0; i < numListenersBeforeEmit; i++ ){199      let listener = listeners[i];200 201      if(202        ( listener.type === eventObj.type ) &&203        ( !listener.namespace || listener.namespace === eventObj.namespace || listener.namespace === universalNamespace ) &&204        ( self.eventMatches( self.context, listener, eventObj ) )205      ){206        let args = [ eventObj ];207 208        if( extraParams != null ){209          util.push( args, extraParams );210        }211 212        self.beforeEmit( self.context, listener, eventObj );213 214        if( listener.conf && listener.conf.one ){215          self.listeners = self.listeners.filter( l => l !== listener );216        }217 218        let context = self.callbackContext( self.context, listener, eventObj );219        let ret = listener.callback.apply( context, args );220 221        self.afterEmit( self.context, listener, eventObj );222 223        if( ret === false ){224          eventObj.stopPropagation();225          eventObj.preventDefault();226        }227      } // if listener matches228    } // for listener229 230    if( self.bubble( self.context ) && !eventObj.isPropagationStopped() ){231      self.parent( self.context ).emit( eventObj, extraParams );232    }233  }, events );234 235  this.emitting--;236 237  return this;238};239 240export default Emitter;241