export class Version { constructor ( readonly versionString ) { } public isV2x ( ) { return this . versionString . startsWith ( '2' ) ; } public isV3x ( ) { return this . versionString . startsWith ( '3' ) ; } public toString ( ) { return this . versionString ; } } /**
 * Exposes some convenience properties for version checking.
 */ export const Versions = { v2x : new Version ( '2' ) , v3x : new Version ( '3' ) , } ;