class YaksokList extends Array { get 길이 ( ) { return ( this [ 0 ] === void 0 ) ? this . length - 1 : this . length ; } * [ Symbol . iterator ] ( ) { for ( let i = this [ 0 ] === void 0 ? 1 : 0 ; i < this . length ; ++ i ) yield this [ i ] ; } toJsArray ( ) { let copy = this . slice ( ) ; copy . shift ( ) ; return copy ; } } YaksokList . prototype . isYaksokList = true ; function yaksokList ( array ) { array . constructor = YaksokList ; array . __proto__ = YaksokList . prototype ; return array ; }