export interface IHostStateHistory { history ? : string [ ] ; } export class HostStateHistory { public static signature : string = 'HostStateHistory' ; public signature : string = HostStateHistory . signature ; public history : string [ ] = [ ] ; constructor ( params ) { if ( typeof params !== 'object' || params === null ) { throw new Error ( `Incorrect parameters for HostStateHistory message` ) ; } this . history = params . history instanceof Array ? params . history : [ ] ; } }