refactor: unified getAmountWithExchange and getAmountWithoutExchange methods (closes #10)

src/transaction/transaction.controller.ts

@@ -33,10 +33,7 @@ export class TransactionController {
     @Body() transactionInput: TransactionInput,
   ): Promise<string> {
     return JSON.stringify({
-      amount:
-        transactionInput.currency !== Currency.EUR
-          ? (await this.getAmountWithExchange(transactionInput)).toFixed(2)
-          : (await this.getAmountWithoutExchange(transactionInput)).toFixed(2),
+      amount: (await this.getCommissionAmount(transactionInput)).toFixed(2),
       currency: Currency.EUR,
     });
   }
@@ -97,7 +94,7 @@ export class TransactionController {
     );
   }
 
-  getExchangeRate(exchangeRateInput: ExchangeRateInput) {
+  getExchangeRateResponse(exchangeRateInput: ExchangeRateInput) {
     return new Promise<ExchangeRateResponse>((resolve, reject) => {
       try {
         this.exchangeRateService.convertCurrency(exchangeRateInput).subscribe({
@@ -110,11 +107,21 @@ export class TransactionController {
     });
   }
 
-  async getAmountWithExchange(transactionInput: TransactionInput) {
-    const exchangeRateResponse = await this.getExchangeRate({
+  async getExchangeRateIfNeeded(transactionInput: TransactionInput) {
+    if (transactionInput.currency === Currency.EUR) {
+      return 1;
+    }
+
+    const exchangeRateResponse = await this.getExchangeRateResponse({
       date: transactionInput.date,
     });
 
+    return exchangeRateResponse[transactionInput.currency];
+  }
+
+  async getCommissionAmount(transactionInput: TransactionInput) {
+    const exchangeRate = await this.getExchangeRateIfNeeded(transactionInput);
+
     const transactionAmount = parseInt(transactionInput.amount);
     const transactionData = {
       date: transactionInput.date,
@@ -122,47 +129,18 @@ export class TransactionController {
       currency: transactionInput.currency,
       client_id: transactionInput.client_id,
       base_currency: Currency.EUR,
-      base_amount:
-        transactionAmount / exchangeRateResponse[transactionInput.currency],
+      base_amount: transactionAmount / exchangeRate,
     };
 
-    const commissionAmount = this.applyRules(transactionData);
-
-    commissionAmount
-      .then((commission) =>
-        this.transactionService.insertOne({
-          ...transactionData,
-          commission,
-        }),
-      )
-      .catch((error) => console.log(error));
+    const commission = await this.applyRules(transactionData);
 
-    return commissionAmount;
-  }
-
-  async getAmountWithoutExchange(transactionInput: TransactionInput) {
-    const transactionData = {
-      date: transactionInput.date,
-      amount: parseInt(transactionInput.amount),
-      currency: transactionInput.currency,
-      client_id: transactionInput.client_id,
-      base_currency: Currency.EUR,
-      base_amount: parseInt(transactionInput.amount),
-    };
-
-    const commissionAmount = await this.applyRules(transactionData);
-    try {
     this.transactionService
       .insertOne({
         ...transactionData,
-          commission: commissionAmount,
+        commission,
       })
       .catch((error) => console.log(error));
-    } catch (error) {
-      console.log(error);
-      throw error;
-    }
 
-    return commissionAmount;
+    return commission;
   }
 }