Add radix sort in JavaScript (#912)

Author: tinniaru3005

Javascript/Algorithms/radix-sort.js

@@ -0,0 +1,42 @@
+const unsortedArr = [31, 27, 28, 42, 13, 3, 50, 46, 25, 18, 33, 47, 4, 45, 39, 23, 2];
+
+const getNum = (num, index) => {
+    const strNum = String(num);
+    let end = strNum.length - 1;
+    const foundNum = strNum[end - index];
+  
+    if (foundNum === undefined) return 0;
+    else return foundNum;
+};
+  
+console.log(getNum(4353, 2));
+
+const largestNum = arr => {
+    let largest = "0";
+  
+    arr.forEach(num => {
+      const strNum = String(num);
+  
+      if (strNum.length > largest.length) largest = strNum;
+    });
+  
+    return largest.length;
+};
+
+const radixSort = arr => {
+    let maxLength = largestNum(arr);
+  
+    for (let i = 0; i < maxLength; i++) {
+      let buckets = Array.from({ length: 10 }, () => []);
+  
+      for (let j = 0; j < arr.length; j++) {
+        let num = getNum(arr[j], i);
+  
+        if (num !== undefined) buckets[num].push(arr[j]);
+      };
+      arr = buckets.flat();
+    };
+    return arr;
+};
+  
+console.log(radixSort(unsortedArr));