added mapSetExercise.js

Author: jonjones320

mapSetExercise.js

@@ -0,0 +1,61 @@
+/////////Quick Question #1////////////////////
+//What does the following code return?
+// new Set([1,1,2,2,3,4])
+
+{1,2,3,4}
+
+/////////Quick Question #2////////////////////
+//What does the following code return?
+// [...new Set("referee")].join("")
+
+"refere"
+
+/////////Quick Question #3////////////////////
+//What does the Map m look like after running the following code?
+// let m = new Map();
+// m.set([1,2,3], true);
+// m.set([1,2,3], false);
+
+// m {
+//     [1,2,3]: true,
+//     [1,2,3]: false,
+// }
+
+
+///////////////////////**hasDuplicate**///////////////////////////////
+//Write a function called hasDuplicate which accepts an array and returns true or false if that array contains a duplicate
+hasDuplicate([1,3,2,1]) // true
+hasDuplicate([1,5,-1,4]) // false
+
+function hasDuplicate(arr) {
+    if (arr.filter(
+        (val) => (!(new Set(arr)).has(val)))
+    ) {
+        return false
+    };
+    return true;
+}
+
+///////////////////////**vowelCount**///////////////////////////////
+
+//Write a function called vowelCount which accepts a string and returns a map where the keys are numbers 
+//and the values are the count of the vowels in the string.
+//vowelCount('awesome') // Map { 'a' => 1, 'e' => 2, 'o' => 1 }
+//vowelCount('Colt') // Map { 'o' => 1 }
+
+const isVowel = (letter) => "aeiou".includes(letter);
+
+function vowelCount (string) {
+    let newMap = new Map();
+    let smallChar = string.toLowerCase();
+
+    for(let char of smallChar) {
+        if (isVowel(char)) {
+            if (newMap.has(char)) {
+                (newMap.set(char, newMap.get(char)+1));
+            }
+            else {newMap.set(char, 1)};
+        }
+    };
+    return newMap;
+}