Use a map

solutions/day7/solution.js

@@ -5,34 +5,24 @@ const report = (...messages) => console.log(`[${require(fromHere('../../package.
 
 async function run () {
   // light red bags contain 1 bright white bag, 2 muted yellow bags.
-  const input = (await read(fromHere('input.txt'), 'utf8')).trim().split('\n').map(
+  const input = new Map();
+  (await read(fromHere('input.txt'), 'utf8')).trim().split('\n').forEach(
     line => {
       const [color, rest] = line.split(' bags contain ')
       let contents
       if (rest === 'no other bags.') contents = []
       else {
-        contents = rest.slice(0, -1).split(', ').map(i => {
-          const [, qty, color] = i.match(/(\d+) (.+) bags?/)
-          return {
+        contents = rest.split(', ').map(i => {
+          const [, qty, color] = i.match(/(\d+) (.+) bags?\.?/)
+          return ({
             quantity: 1 * qty,
             color
-          }
+          })
         })
       }
-      return {
-        color,
-        contents
-      }
+      input.set(color, contents)
     }
-  ).reduce((acc, cur) => ({ ...acc, [cur.color]: cur.contents }), {})
-  /*
-{
-  color
-  contents: [
-    { quantity, color}
-  ]
-}
-*/
+  )
 
   await solveForFirstStar(input)
   await solveForSecondStar(input)
@@ -40,7 +30,7 @@ async function run () {
 
 async function solveForFirstStar (input) {
   const outerColors = new Set()
-  Object.entries(input).forEach(([color, contents]) => {
+  input.forEach((contents, color) => {
     if (contents.some(
       bag => bag.color === 'shiny gold')
     ) {
@@ -50,8 +40,8 @@ async function solveForFirstStar (input) {
   let oldSize
   while (oldSize !== outerColors.size) {
     oldSize = outerColors.size
-    Object.entries(input).forEach(
-      ([color, contents]) => {
+    input.forEach(
+      (contents, color) => {
         if (
           !outerColors.has(color) &&
           contents.some(bag => outerColors.has(bag.color))
@@ -67,8 +57,8 @@ async function solveForFirstStar (input) {
 }
 
 function count (input, color) {
-  if (input[color].length === 0) return 1
-  return input[color].reduce((acc, bag) => acc + bag.quantity * count(input, bag.color), 1)
+  if (input.get(color).length === 0) return 1
+  return input.get(color).reduce((acc, bag) => acc + bag.quantity * count(input, bag.color), 1)
 }
 
 async function solveForSecondStar (input) {