solve Day08 in JS/TS

Day08/js/solution.js

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+const fs = require('fs');
+const path = require('path');
+
+function gcd(a, b) {
+    while (b !== 0) {
+        let t = b;
+        b = a % b;
+        a = t;
+    }
+    return a;
+}
+
+function lcm(a, b) {
+    return (a * b) / gcd(a, b);
+}
+
+function parseFile(filePath) {
+    console.log(`Parsing file: ${filePath}`);
+    const data = fs.readFileSync(filePath, 'utf8').trim();
+    const [stepsSection, rulesSection] = data.split('\n\n');
+    const steps = stepsSection.split('').map(char => char === 'L' ? 0 : 1);
+    const rules = rulesSection.split('\n').reduce((acc, line) => {
+        const [state, directions] = line.split('=').map(s => s.trim());
+        const [left, right] = directions.split(',').map(s => s.trim());
+        acc['L'][state] = left.slice(1);
+        acc['R'][state] = right.slice(0, -1);
+        return acc;
+    }, { 'L': {}, 'R': {} });
+
+    return { steps, rules };
+}
+
+function navigateNetworkSimultaneously(steps, rules) {
+    console.log("Starting navigation of network.");
+    const startNodes = Object.keys(rules['L']).filter(node => node.endsWith('A'));
+    let currentNodes = startNodes;
+    let stepCount = 0;
+    const timeToZ = {};
+
+    while (Object.keys(timeToZ).length < startNodes.length) {
+        currentNodes.forEach((node, index) => {
+            const direction = steps[stepCount % steps.length] === 0 ? 'L' : 'R';
+            const nextNode = rules[direction][node];
+            currentNodes[index] = nextNode;
+            if (nextNode.endsWith('Z') && !(index in timeToZ)) {
+                timeToZ[index] = stepCount + 1;
+            }
+        });
+        stepCount++;
+        console.log(`Step ${stepCount}: Current nodes - ${currentNodes}`);
+    }
+
+    return Object.values(timeToZ).reduce((acc, val) => lcm(acc, val), 1);
+}
+
+function runTest() {
+    console.log("Running test...");
+    const testPath = path.join(__dirname, '../test.txt');
+    const { steps, rules } = parseFile(testPath);
+    const expected = 6;
+    const result = navigateNetworkSimultaneously(steps, rules);
+
+    if (result !== expected) {
+        throw new Error(`Test failed: expected ${expected}, got ${result}`);
+    }
+
+    console.log(`Test passed with ${result} steps.`);
+}
+
+function main() {
+    try {
+        runTest();
+        const inputPath = path.join(__dirname, '../input.txt');
+        const { steps, rules } = parseFile(inputPath);
+        const result = navigateNetworkSimultaneously(steps, rules);
+        console.log(`All paths reached 'Z' nodes simultaneously in ${result} steps.`);
+    } catch (error) {
+        console.error(`Error: ${error.message}`);
+    }
+}
+
+main();