const NS_NAME = 'ESL' ; /**
 * Nested declaration helper
 */ function define ( root , name , value ) { name . split ( '.' ) . reduce ( ( obj , key , index , parts ) => { if ( parts . length === index + 1 ) { return ( obj [ key ] = obj [ key ] || value ) ; } const type = typeof obj [ key ] ; if ( type !== 'undefined' && type !== 'object' && type !== 'function' ) { throw new Error ( `Can not define ${ value } on ${ name }` ) ; } return ( obj [ key ] = obj [ key ] || { } ) ; } , root ) ; } /**
 * Method to manually declare key in library namespace
 * See  ExportNs decorator for details
  export const exportNs = ( name , module ) : void => { if ( ! ( NS_NAME in window ) ) return ; define ( ( window as any ) [ NS_NAME ] , name , module ) ; } ; param name example Export export function ExportNs < T extends Function > ( name ? ) { return ( module ) : void => exportNs ( name || module . name , module ) ; } /** Declare ESL global */ ExportNs . declare = ( ) : void => { if ( 'ESL' in window ) return ; Object . defineProperty ( window , 'ESL' , { value : { } } ) ; } ;