()
| 120 | next: MapKey<K> | undefined = undefined |
| 121 | constructor(readonly current: K) {} |
| 122 | [Hash.symbol](): number { |
| 123 | return pipe( |
| 124 | Hash.hash(this.current), |
| 125 | Hash.combine(Hash.hash(this.previous)), |
| 126 | Hash.combine(Hash.hash(this.next)), |
| 127 | Hash.cached(this) |
| 128 | ) |
| 129 | } |
| 130 | [Equal.symbol](that: unknown): boolean { |
| 131 | if (this === that) { |
| 132 | return true |