1 files changed, 54 insertions, 2 deletions
diff --git a/day4/index.ts b/day4/index.ts
index 1d059dc..2ee8775 100644
--- a/day4/index.ts
+++ b/day4/index.ts
@@ -26,7 +26,7 @@ const parsePassports = (input: string): Passport[] => {
   return result;
 }
 
-const isPassportValid = (passport: Passport): boolean => {
+const requiredFieldsPresent = (passport: Passport): boolean => {
   const requiredKeys = ["byr", "iyr", "eyr", "hgt", "hcl", "ecl", "pid"];
 
   let valid = true;
@@ -38,15 +38,67 @@ const isPassportValid = (passport: Passport): boolean => {
   return valid;
 }
 
+const byrValid = (byr: string): boolean => {
+  const match = byr.match(/\d{4}/);
+  if (!match) return false;
+  const val = Number(match[0]);
+  return val >= 1920 && val <= 2002;
+}
+
+const iyrValid = (iyr: string): boolean => {
+  const match = iyr.match(/\d{4}/);
+  if (!match) return false;
+  const val = Number(match[0]);
+  return val >= 2010 && val <= 2020;
+}
+
+const eyrValid = (eyr: string): boolean => {
+  const match = eyr.match(/\d{4}/);
+  if (!match) return false;
+  const val = Number(match[0]);
+  return val >= 2020 && val <= 2030;
+}
+
+const hgtValid = (hgt: string): boolean => {
+  const match = hgt.match(/(\d{2,3})(cm|in)/);
+  if (!match) return false;
+  const val = Number(match[1]);
+  const unit = match[2];
+  return (unit === "cm" && val >= 150 && val <= 193) || (unit === "in" && val >= 59 && val <= 76);
+}
+
+const hclValid = (hcl: string): boolean => !!hcl.match(/\#[0-9a-f]{6}/);
+
+const eclValid = (ecl: string): boolean => ["amb", "blu", "brn", "gry", "grn", "hzl", "oth"].includes(ecl);
+
+const pidValid = (pid: string): boolean => !!pid.match(/\d{9}/);
+
+const isPassportValid = (passport: Passport): boolean =>
+  requiredFieldsPresent(passport)
+  && byrValid(passport.byr)
+  && iyrValid(passport.iyr)
+  && eyrValid(passport.eyr)
+  && hgtValid(passport.hgt)
+  && hclValid(passport.hcl)
+  && eclValid(passport.ecl)
+  && pidValid(passport.pid)
+
 const day4: ExerciseModuleFunc = async (input: string) => {
   const prom1 = of(input).pipe(
     map(parsePassports),
     concatAll(),
+    filter(requiredFieldsPresent),
+    count()
+  ).toPromise();
+
+  const prom2 = of(input).pipe(
+    map(parsePassports),
+    concatAll(),
     filter(isPassportValid),
     count()
   ).toPromise();
 
-  return Promise.all([prom1]);
+  return Promise.all([prom1, prom2]);
 }
 
 export default day4;