Add helper function to format money values

src/util/currency.js

@@ -168,3 +168,23 @@ export const convertMoneyToNumber = (value, subUnitDivisor) => {
   const amount = new Decimal(value.amount);
   return amount.dividedBy(subUnitDivisorAsDecimal).toNumber();
 };
+
+/**
+ * Format the given money to a string
+ *
+ * @param {Object} intl
+ * @param {Object} currencyConfig
+ * @param {Money} value
+ *
+ * @return {String} formatted money value
+ */
+export const formatMoney = (intl, currencyConfig, value) => {
+  if (!(value instanceof types.Money)) {
+    throw new Error('Value must be a Money type');
+  }
+  if (value.currency !== currencyConfig.currency) {
+    throw new Error('Given currency different from marketplace currency');
+  }
+  const valueAsNumber = convertMoneyToNumber(value, currencyConfig.subUnitDivisor);
+  return intl.formatNumber(valueAsNumber, currencyConfig);
+};

src/util/currency.test.js

@@ -7,6 +7,7 @@ import {
   convertUnitToSubUnit,
   ensureSeparator,
   truncateToSubUnitPrecision,
+  formatMoney,
 } from './currency';
 
 describe('currency utils', () => {
@@ -214,4 +215,27 @@ describe('currency utils', () => {
       );
     });
   });
+
+  describe('formatMoney', () => {
+    it('complains about incorrect value type', () => {
+      const intl = null;
+      const currencyConfig = {};
+      const value = null;
+      expect(() => formatMoney(intl, currencyConfig, value)).toThrowError(
+        'Value must be a Money type'
+      );
+    });
+    it('complains about mismatching currencies', () => {
+      const intl = null;
+      const currencyConfig = { currency: 'USD' };
+      const value = new types.Money(100, 'EUR');
+      expect(() => formatMoney(intl, currencyConfig, value)).toThrowError(
+        'Given currency different from marketplace currency'
+      );
+    });
+
+    // No test for that actual formatting for now. It depends on the
+    // locale, and it doesn't really make sense to test the fake intl
+    // implementation in the tests.
+  });
 });