day 4 solved

solutions/day4/solution.js

@@ -0,0 +1,75 @@
+const path = require('path')
+const { read, position } = require('promise-path')
+const fromHere = position(__dirname)
+const report = (...messages) => console.log(`[${require(fromHere('../../package.json')).logName} / ${__dirname.split(path.sep).pop()}]`, ...messages)
+
+async function run () {
+  const input = (await read(fromHere('input.txt'), 'utf8')).trim().split('\n\n').map(
+    line => line.replace(/\n/g, ' ').split(' ').reduce((acc, cur) => {
+      const [key, value] = cur.split(':')
+      return { ...acc, [key]: value }
+    }, {})
+  )
+
+  await solveForFirstStar(input)
+  await solveForSecondStar(input)
+}
+
+const required = [
+  'byr',
+  'iyr',
+  'eyr',
+  'hgt',
+  'hcl',
+  'ecl',
+  'pid'
+]
+
+const between = (a, b, c) => {
+  return a <= b && b <= c
+}
+
+const validators = {
+  byr: x => between(1920, parseInt(x), 2002),
+  iyr: x => between(2010, parseInt(x), 2020),
+  eyr: x => between(2020, parseInt(x), 2030),
+  hgt: x => {
+    const parsed = x.match(/(\d+)(cm|in)/)
+    if (!parsed) return false
+    const [, height, units] = parsed
+    if (units === 'cm') {
+      return between(150, parseInt(height), 193)
+    } else if (units === 'in') {
+      return between(59, parseInt(height), 76)
+    } else return false
+  },
+  hcl: x => /^#[0-9a-f]{6}$/.test(x),
+  ecl: x => ['amb', 'blu', 'brn', 'gry', 'grn', 'hzl', 'oth'].includes(x),
+  pid: x => /^[0-9]{9}$/.test(x)
+}
+
+function isValid (line) {
+  for (const key of required) {
+    console.log(Object.keys(line), key)
+    if (!Object.keys(line).includes(key)) { return false }
+  }
+  return true
+}
+
+async function solveForFirstStar (input) {
+  const solution = input.filter(isValid).length
+  report('Input:', input)
+  report('Solution 1:', solution)
+}
+
+async function solveForSecondStar (input) {
+  const solution = input.filter(doc => {
+    for (const [key, validator] of Object.entries(validators)) {
+      if (!validator(doc[key])) return false
+    }
+    return true
+  }).length
+  report('Solution 2:', solution)
+}
+
+run()