[FIX] Type detection for UPC (UPC_E = EAN_8)

src/__tests__/barcode-type-detector.test.ts

@@ -1,18 +1,14 @@
-import { BarcodeTypeDetector } from '../barcode-type-detector';
+import {BarcodeTypeDetector} from '../barcode-type-detector';
 import { BarcodeType } from '../enums';
 
-test('EAN_13', () => {
+test('EAN_13 Validation', () => {
   expect(BarcodeTypeDetector.detect('3614950268099')).toBe(BarcodeType.EAN_13);
 });
 
-test('EAN_8', () => {
+test('EAN_8 Validation', () => {
   expect(BarcodeTypeDetector.detect('78635708')).toBe(BarcodeType.EAN_8);
 });
 
-test('UPC_A', () => {
-  expect(BarcodeTypeDetector.detect('012345678905')).toBe(BarcodeType.UPC_A);
-});
-
-test('UPC_E', () => {
-  expect(BarcodeTypeDetector.detect('8635709')).toBe(BarcodeType.UPC_E);
+test('UPC_A Validation', () => {
+  expect(BarcodeTypeDetector.detect('123456789104')).toBe(BarcodeType.UPC_A);
 });

src/barcode-type-detector.ts

@@ -18,27 +18,28 @@ const onlyDigitsRegexp = (length: number): RegExp => new RegExp(`^\\d{${length}}
  */
 const isOnlyDigits = (value: string, length: number): boolean => onlyDigitsRegexp(length).test(value);
 /**
- * EAN control key system based on the Luhn formula
+ * Control key calculation
  * @param value
  */
-const eanKeyController = (value: string): boolean => {
-  const lastIndex = value.length - 1;
+const getEanControlKey = (value: string): number => {
   const sumCtrl = value
-    .slice(0, lastIndex)
-    .split('')
-    // Chars are only digits
-    .map(digit => parseInt(digit, 10))
-    // Each even char column index is multiply by 3
-    // And we make the sum
-    .reduce((acc, digit, index) => acc + (index % 2 ? digit : digit * 3), 0);
-  // The calculated control key has to be the same as the last char in value
-  return parseInt(value.slice(lastIndex), 10) === 10 - (sumCtrl % 10);
+      .slice(0, value.length - 1)
+      .split('')
+      // Chars are only digits
+      .map(digit => parseInt(digit, 10))
+      // Each even char column index is multiply by 3
+      // And we make the sum
+      .reduce((acc, digit, index) => acc + ((index % 2) ? digit : (digit * 3)), 0);
+  return 10 - (sumCtrl % 10);
 };
 /**
- * UPC uses the same control key system as EAN but we have to add a 0 at the beginning of value
+ * EAN and UPC control key system based on the Luhn formula
  * @param value
  */
-const upcKeyController = (value: string): boolean => eanKeyController(`0${value}`);
+const eanKeyController = (value: string): boolean => {
+  // The calculated control key has to be the same as the last char in value
+  return parseInt(value.slice(value.length - 1), 10) === getEanControlKey(value);
+};
 /**
  * Is the value an EAN with specified length ?
  * @param value
@@ -50,23 +51,19 @@ const isEan = (value: string, length: 8 | 13): boolean => isOnlyDigits(value, le
  * @param value
  * @param length
  */
-const isUpc = (value: string, length: 7 | 12): boolean => isOnlyDigits(value, length) && upcKeyController(value);
+const isUpc = (value: string): boolean => isOnlyDigits(value, 12) && eanKeyController(value);
 /**
  * EAN_13 = ONLY 13 digits + control key checking
  */
 const ean13Definer: IBarcodeTypeDefiner = { method: value => isEan(value, 13), type: BarcodeType.EAN_13 };
 /**
  * UPC_A = ONLY 12 digits + control key checking
  */
-const upcADefiner: IBarcodeTypeDefiner = { method: value => isUpc(value, 12), type: BarcodeType.UPC_A };
+const upcADefiner: IBarcodeTypeDefiner = { method: value => isUpc(value), type: BarcodeType.UPC_A };
 /**
  * EAN_8 = ONLY 8 digits + control key checking
  */
 const ean8Definer: IBarcodeTypeDefiner = { method: value => isEan(value, 8), type: BarcodeType.EAN_8 };
-/**
- * UPC_E = ONLY 7 digits + control key checking
- */
-const upcEDefiner: IBarcodeTypeDefiner = { method: value => isUpc(value, 7), type: BarcodeType.UPC_E };
 /**
  * Detector of barcode type
  */
@@ -87,5 +84,5 @@ export class BarcodeTypeDetector {
   /**
    * List of definers
    */
-  private static readonly definers: IBarcodeTypeDefiner[] = [ean13Definer, upcADefiner, ean8Definer, upcEDefiner];
+  private static readonly definers: IBarcodeTypeDefiner[] = [ean13Definer, upcADefiner, ean8Definer];
 }