♻️ 【第3章三角測量】null との等値性比較の実装

dodonki1223 · Dec 7, 2021 · 2b76bae · 2b76bae
1 parent c5788d5
commit 2b76bae
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diff --git a/TODO.md b/TODO.md
@@ -3,5 +3,5 @@
 - [ ] amount を private にする
 - [x] Dollar の副作用どうする？
 - [ ] Money の丸め処理どうする？
-- [ ] nullとの等価性比較
+- [x] nullとの等価性比較
 - [x] equals()メソッドの実装
diff --git a/src/dollar.ts b/src/dollar.ts
@@ -7,7 +7,11 @@ export class Dollar {
     return new Dollar(this.amount * multiplier)
   }
 
-  equals(dollar: Dollar) {
+  equals(dollar: Dollar | null) {
+    if (dollar === null) {
+        return false;
+    }
+
     return this.amount === dollar.amount
   }
 }