From 1a3a2639ba8381a5b22cbb15c4a9507c841e2394 Mon Sep 17 00:00:00 2001
From: Higor Castilho <castilhohf@gmail.com>
Date: Fri, 11 Sep 2020 09:21:01 -0300
Subject: [PATCH] Create HexToDecimal.js

 Hello. Hope this can be useful to conversions in JavaScript repository :)
---
 Conversions/HexToDecimal.js | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)
 create mode 100644 Conversions/HexToDecimal.js

diff --git a/Conversions/HexToDecimal.js b/Conversions/HexToDecimal.js
new file mode 100644
index 0000000000..8627dbcf7d
--- /dev/null
+++ b/Conversions/HexToDecimal.js
@@ -0,0 +1,27 @@
+function hexToInt (hexNum) {
+  const numArr = hexNum.split('') // converts number to array
+  numArr.map((item, index) => {
+    if (!(item > 0)) {
+      switch (item) {
+        case 'A': return (numArr[index] = 10)
+        case 'B': return (numArr[index] = 11)
+        case 'C': return (numArr[index] = 12)
+        case 'D': return (numArr[index] = 13)
+        case 'E': return (numArr[index] = 14)
+        case 'F': return (numArr[index] = 15)
+      }
+    } else numArr[index] = parseInt(item)
+  })
+  return numArr // returns an array only with integer numbers
+}
+
+function hexToDecimal (hexNum) {
+  const intItemsArr = hexToInt(hexNum)
+  return intItemsArr.reduce((accumulator, current, index) => {
+    return accumulator + (current * Math.pow(16, (intItemsArr.length - (1 + index))))
+  }, 0)
+}
+
+// test cases
+console.log(hexToDecimal('5DE9A')) // 384666
+console.log(hexToDecimal('3D')) // 61