Add solution #1002

Author: JoshCrozier

README.md

@@ -174,6 +174,7 @@
 989|[Add to Array-Form of Integer](./0989-add-to-array-form-of-integer.js)|Easy|
 994|[Rotting Oranges](./0994-rotting-oranges.js)|Medium|
 997|[Find the Town Judge](./0997-find-the-town-judge.js)|Easy|
+1002|[Find Common Characters](./1002-find-common-characters.js)|Easy|
 1009|[Complement of Base 10 Integer](./1009-complement-of-base-10-integer.js)|Easy|
 1010|[Pairs of Songs With Total Durations Divisible by 60](./1010-pairs-of-songs-with-total-durations-divisible-by-60.js)|Medium|
 1022|[Sum of Root To Leaf Binary Numbers](./1022-sum-of-root-to-leaf-binary-numbers.js)|Easy|

solutions/1002-find-common-characters.js

@@ -0,0 +1,24 @@
+/**
+ * 1002. Find Common Characters
+ * https://leetcode.com/problems/find-common-characters/
+ * Difficulty: Easy
+ *
+ * Given a string array words, return an array of all characters that show up in all strings within
+ * the words (including duplicates). You may return the answer in any order.
+ */
+
+/**
+ * @param {string[]} words
+ * @return {string[]}
+ */
+var commonChars = function(words) {
+  return words
+    .map(word => [...word])
+    .reduce((common, word) => common.filter(s => {
+      const index = word.indexOf(s);
+      if (index !== -1) {
+        word.splice(index, 1);
+      }
+      return index !== -1;
+    }), [...words[0]]);
+};