1 files changed, 47 insertions, 0 deletions
diff --git a/day2/index.ts b/day2/index.ts
new file mode 100644
index 0000000..e42e005
--- /dev/null
+++ b/day2/index.ts
@@ -0,0 +1,47 @@
+import { of } from "rxjs";
+import { concatAll, count, filter, map, take } from 'rxjs/operators';
+import { ExerciseModuleFunc } from "../types";
+
+interface Row {
+  min: number;
+  max: number;
+  letter: string;
+  pwd: string;
+}
+
+const parse = (line: string): Row => {
+  const re = /(\d+)-(\d+) (\w{1}): (\w+)/;
+  const match = line.match(re);
+
+  return {
+    min: Number(match[1]),
+    max: Number(match[2]),
+    letter: match[3],
+    pwd: match[4]
+  }
+}
+
+const isValid = (r: Row): boolean => {
+  let count = 0;
+  r.pwd.split("").forEach(char => {
+    if (char === r.letter) {
+      count += 1;
+    }
+  });
+  return count >= r.min && count <= r.max;
+}
+
+const day2: ExerciseModuleFunc = async (input: string) => {
+  const lines = input.split("\n");
+
+  const prom1 = of(lines).pipe(
+    concatAll(),
+    map(parse),
+    filter(isValid),
+    count()
+  ).toPromise();
+
+  return [await prom1];
+}
+
+export default day2;