nl_tokens: A Set is a list with only unique values . ( No duplication . )
pl_tokens: function storagePushToSet ( [ key , value ] ) { log ( 'storagePushToSet' , key , value ) ; const item = getLocalStorageItem ( key ) ; const list = Array . isArray ( item ) ? item : [ ] ; if ( list . indexOf ( value ) === - 1 ) { list . push ( value ) ; } setLocalStorageItem ( <mask> , list ) ; }