initial solution

src/2023/day01.js

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+export function part1(input) {
+  const lines = input.split('\n');
+  const nums = lines.map(line => {
+    const first = +line.split('').find(c => c >= '0' && c <= '9');
+    const last = +line
+      .split('')
+      .reverse()
+      .find(c => c >= '0' && c <= '9');
+    return first * 10 + last;
+  });
+  return nums.reduce((a, b) => a + b, 0);
+}
+
+export function part2(input) {
+  const letters = [
+    'zero',
+    'one',
+    'two',
+    'three',
+    'four',
+    'five',
+    'six',
+    'seven',
+    'eight',
+    'nine',
+    '0',
+    '1',
+    '2',
+    '3',
+    '4',
+    '5',
+    '6',
+    '7',
+    '8',
+    '9',
+  ];
+  const lines = input.split('\n');
+  const nums = lines.map(line => {
+    const first = letters
+      .map(n => ({ n, i: line.indexOf(n) }))
+      .filter(x => x.i > -1)
+      .sort((a, b) => a.i - b.i)[0].n;
+    const last = letters
+      .map(n => ({ n, i: line.lastIndexOf(n) }))
+      .filter(x => x.i > -1)
+      .sort((a, b) => b.i - a.i)[0].n;
+
+    const a = letters.indexOf(first) <= 9 ? letters.indexOf(first) : +first;
+    const b = letters.indexOf(last) <= 9 ? letters.indexOf(last) : +last;
+    return a * 10 + b;
+  });
+  return nums.reduce((a, b) => a + b, 0);
+}

src/2023/day01.spec.js

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+import { part1, part2 } from './day01.js';
+import readInput from '../utils/read-input.js';
+
+const input = readInput(import.meta.url);
+
+describe('day01 2023', () => {
+  describe('part1', () => {
+    it('should work for part 1 examples', () => {
+      expect(
+        part1(['1abc2', 'pqr3stu8vwx', 'a1b2c3d4e5f', 'treb7uchet'].join('\n')),
+      ).toEqual(142);
+    });
+
+    it('should work for part 1 input', () => {
+      expect(part1(input)).toEqual(54953);
+    });
+  });
+
+  describe('part2', () => {
+    it('should work for part 2 examples', () => {
+      expect(
+        part2(
+          [
+            'two1nine',
+            'eightwothree',
+            'abcone2threexyz',
+            'xtwone3four',
+            '4nineeightseven2',
+            'zoneight234',
+            '7pqrstsixteen',
+          ].join('\n'),
+        ),
+      ).toEqual(281);
+    });
+
+    it('should work for part 2 input', () => {
+      expect(part2(input)).toEqual(53868);
+    });
+  });
+});