nl_tokens: This attaches PAGE_MIXIN methods to page / middleware classes . It does this only _once_ and thereafter short - circuits .
pl_tokens: function lazyMixinPageUtilMethods ( page ) { var proto = Object . getPrototypeOf ( page ) ; if ( proto . _haveMixedInPageUtilMethods ) return ; proto . _haveMixedInPageUtilMethods = true ; Object . keys ( PAGE_MIXIN ) . forEach ( method => { if ( proto [ method ] ) { throw new Error ( ` ${ ( proto . constructor || { } ) . <mask> } ${ method } ` ) ; } proto [ method ] = PAGE_MIXIN [ method ] ; } ) ; }