From 24e55c105c13adb21f0483edde0376c24e2d8ebc Mon Sep 17 00:00:00 2001
From: Piyush Katyal <109459034+piyushk77@users.noreply.github.com>
Date: Wed, 11 Oct 2023 02:31:18 +0530
Subject: [PATCH 1/2] feat: add binary to BCD conversion algorithm

---
 Conversions/BinaryToBcd.js | 68 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 68 insertions(+)
 create mode 100644 Conversions/BinaryToBcd.js

diff --git a/Conversions/BinaryToBcd.js b/Conversions/BinaryToBcd.js
new file mode 100644
index 0000000000..4ffd618d84
--- /dev/null
+++ b/Conversions/BinaryToBcd.js
@@ -0,0 +1,68 @@
+/**
+ * Generates a Binary Coded Decimal (BCD 4-bit representation) equivalent of given binary number.
+ * @param {string} binaryInput - Binary number in string format to be converted to BCD.
+ * @returns {string} - A string equivalent of binary coded decimal (4-bit representation).
+ *
+ * @see
+ * For more info: https://en.wikipedia.org/wiki/Binary-coded_decimal
+ *
+ * @example
+ * const binaryInput = '1100010010'
+ * const bcdNum = binaryToBcd(decimal)
+ * // bcdNum will be '11110000110'
+ */
+
+const bcdEquivalent = (decimalCharacter) => {
+  switch (decimalCharacter) {
+    case '0':
+      return '0000'
+    case '1':
+      return '0001'
+    case '2':
+      return '0010'
+    case '3':
+      return '0011'
+    case '4':
+      return '0100'
+    case '5':
+      return '0101'
+    case '6':
+      return '0110'
+    case '7':
+      return '0111'
+    case '8':
+      return '1000'
+    case '9':
+      return '1001'
+  }
+}
+
+const isValidBinary = (binaryInput) => {
+  for (let i = 0; i < binaryInput.length; i++) {
+    if (binaryInput[i] !== '0' && binaryInput[i] !== '1') {
+      return false
+    }
+  }
+  return true
+}
+
+const binaryToBcd = (binaryInput) => {
+  if (!isValidBinary(binaryInput)) {
+    throw new Error('Input is not a valid binary number.')
+  }
+
+  let decimalInput = parseInt(binaryInput, 2)
+  let decimalString = decimalInput.toString()
+  let bcdNum = ''
+  for (let i = 0; i < decimalString.length; i++) {
+    bcdNum += bcdEquivalent(decimalString[i])
+  }
+
+  // Remove unnecessary trailing zeros
+  let tempDecimal = parseInt(bcdNum, 2)
+  bcdNum = tempDecimal.toString(2)
+
+  return bcdNum
+}
+
+export { binaryToBcd }

From bd0aaa49ee34d4b1a60d5e63a34833e48f82efc9 Mon Sep 17 00:00:00 2001
From: Piyush Katyal <109459034+piyushk77@users.noreply.github.com>
Date: Wed, 11 Oct 2023 02:33:41 +0530
Subject: [PATCH 2/2] test: add self-tests for binary to BCD algorithm

---
 Conversions/test/BinaryToBcd.test.js | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)
 create mode 100644 Conversions/test/BinaryToBcd.test.js

diff --git a/Conversions/test/BinaryToBcd.test.js b/Conversions/test/BinaryToBcd.test.js
new file mode 100644
index 0000000000..0b47030e02
--- /dev/null
+++ b/Conversions/test/BinaryToBcd.test.js
@@ -0,0 +1,25 @@
+import { binaryToBcd } from '../BinaryToBcd'
+describe('Binary To BCD', () => {
+  test.each([
+    ['1101101001', '100001110011'],
+    ['11101111', '1000111001'],
+    ['1010100010110', '101001110011000'],
+    ['1111101000', '1000000000000'],
+    ['111111111111111', '110010011101100111']
+  ])(
+    'Should return the equivalent BCD of the binary number.',
+    (binaryNum, expected) => {
+      expect(binaryToBcd(binaryNum)).toEqual(expected)
+    }
+  )
+
+  test.each([
+    ['111100001230', 'Input is not a valid binary number.'],
+    ['781df', 'Input is not a valid binary number.'],
+    ['0897111', 'Input is not a valid binary number.'],
+    ['Dsd1022', 'Input is not a valid binary number.'],
+    ['00000000000@#$%', 'Input is not a valid binary number.']
+  ])('Should return the error message.', (binaryNum, expected) => {
+    expect(() => binaryToBcd(binaryNum)).toThrowError(expected)
+  })
+})