Use deep copy instead of shallow copy for the undercut strategy

src/libs/modals/modals/ModalDuplicateStrategy/utils.ts

@@ -1,32 +1,54 @@
 import type { Strategy } from 'libs/queries';
 import { SafeDecimal } from 'libs/safedecimal';
 
+const replaceDecimal = (key: string, value: any) => {
+  if (value instanceof SafeDecimal)
+    return { __type__: 'SafeDecimal', value: value.toString() };
+  return value;
+};
+const reviveDecimal = (key: string, value: any) => {
+  if (
+    typeof value === 'object' &&
+    value !== null &&
+    value['__type__'] === 'SafeDecimal'
+  )
+    return new SafeDecimal(value.value);
+  return value;
+};
+
+export const deepCopy = (obj: any): any =>
+  JSON.parse(JSON.stringify(obj, replaceDecimal), reviveDecimal);
+
 export const getUndercutStrategy = (
   strategy: Strategy,
   undercutDifference: number
 ): Strategy => {
-  const multiplyRate = (rate: string, factor: number) =>
+  const multiplyByRate = (rate: string, factor: number) =>
     new SafeDecimal(rate).times(factor).toString();
 
-  const undercutStrategy = {
-    ...strategy,
-    order0: {
-      ...strategy.order0,
-      startRate: multiplyRate(
-        strategy.order0.startRate,
-        1 + undercutDifference
-      ),
-      endRate: multiplyRate(strategy.order0.endRate, 1 + undercutDifference),
-    },
-    order1: {
-      ...strategy.order1,
-      startRate: multiplyRate(
-        strategy.order1.startRate,
-        1 - undercutDifference
-      ),
-      endRate: multiplyRate(strategy.order1.endRate, 1 - undercutDifference),
-    },
-  };
+  if (undercutDifference < 0 || undercutDifference > 1)
+    throw new Error(
+      'undercutDifference must be less than or equal to 1, and higher than or equal to 0'
+    );
+
+  const undercutStrategy = deepCopy(strategy);
+
+  undercutStrategy.order0.startRate = multiplyByRate(
+    strategy.order0.startRate,
+    1 + undercutDifference
+  );
+  undercutStrategy.order0.endRate = multiplyByRate(
+    strategy.order0.endRate,
+    1 + undercutDifference
+  );
+  undercutStrategy.order1.startRate = multiplyByRate(
+    strategy.order1.startRate,
+    1 - undercutDifference
+  );
+  undercutStrategy.order1.endRate = multiplyByRate(
+    strategy.order1.endRate,
+    1 - undercutDifference
+  );
 
   return undercutStrategy;
 };