Done exercise-1

8-using-inheritance/exercises/exercise-1.js

@@ -0,0 +1,26 @@
+"use strict";
+
+class FunctionalSet extends Set {
+  filter(predicate) {
+    return new FunctionalSet([...this].filter(predicate));
+  }
+  map(mapper) {
+    return new FunctionalSet([...this].map(mapper));
+  }
+  reduce(accumulator, identity) {
+    return [...this].reduce(accumulator, identity);
+  }
+}
+
+const set = new FunctionalSet(["Jack", "Jill", "Tom", "Jerry"]);
+
+const jSet = set.filter((name) => name.startsWith("J"));
+const allCaps = set.map((name) => name.toUpperCase());
+
+const totalLengthOfJWords = set
+  .filter((name) => name.startsWith("J"))
+  .reduce((total, word) => total + word.length, 0);
+
+console.log(jSet);
+console.log(allCaps);
+console.log(totalLengthOfJWords);