feat(2020-day-07): parse a bag rule into an addressable object

Author: developher-net

2020/day-7/bagRules.js

@@ -0,0 +1,24 @@
+const parseRule = (rule) => {
+  const result = {}
+  // Get the color of the outer bag
+  const outRemainder = rule.split(' contain ')
+  result.outer = outRemainder.shift().replace('bags', 'bag')
+  // Get the color and values of inner bags
+  if (outRemainder[0] !== 'no other bags.') {
+    result.inner = outRemainder[0].split(', ').map((str) => {
+      const inRemainder = str.split(' ')
+      const count = Number(inRemainder.shift())
+      const color = inRemainder.join(' ').replace('s.', '')
+      return {
+        count,
+        color
+      }
+    })
+  }
+
+  return result
+}
+
+module.exports = {
+  parseRule
+}

2020/day-7/bagRules.test.js

@@ -0,0 +1,43 @@
+/* eslint-env mocha */
+const { expect } = require('chai')
+const { parseRule } = require('./bagRules')
+
+const testData = {
+  rules: [
+    'light red bags contain 1 bright white bag, 2 muted yellow bags.',
+    'dark orange bags contain 3 bright white bags, 4 muted yellow bags.',
+    'bright white bags contain 1 shiny gold bag.',
+    'muted yellow bags contain 2 shiny gold bags, 9 faded blue bags.',
+    'shiny gold bags contain 1 dark olive bag, 2 vibrant plum bags.',
+    'dark olive bags contain 3 faded blue bags, 4 dotted black bags.',
+    'vibrant plum bags contain 5 faded blue bags, 6 dotted black bags.',
+    'faded blue bags contain no other bags.',
+    'dotted black bags contain no other bags.'
+  ]
+}
+
+describe('--- Day 7: Handy Haversacks ---', () => {
+  describe('Part 1', () => {
+    describe('parseRule()', () => {
+      it('converts a natural language rule into a useable object', () => {
+        expect(parseRule(testData.rules[0])).to.deep.equal({
+          outer: 'light red bag',
+          inner: [
+            {
+              count: 1,
+              color: 'bright white bag'
+            }, {
+              count: 2,
+              color: 'muted yellow bag'
+            }
+          ]
+        })
+      })
+      it('handles bags that do not accept children', () => {
+        expect(parseRule(testData.rules[7])).to.deep.equal({
+          outer: 'faded blue bag'
+        })
+      })
+    })
+  })
+})