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adds code for chapters 06...08`
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‎src/chapter_06.1/index.js‎

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const http = require("node:http");
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const PORT = 5255;
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const server = http.createServer((request, response) => {
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const { headers, data, statusCode } = handleRequest(request);
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response.writeHead(statusCode, headers);
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response.end(data);
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});
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// The header that needs to be sent on every response.
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const baseHeader = {
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"Content-Type": "text/plain",
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};
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const routeHandlers = {
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"GET /": () => ({ statusCode: 200, data: "Hello World!", headers: { "My-Header": "Hello World!" } }),
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"POST /echo": () => ({ statusCode: 201, data: "Yellow World!", headers: { "My-Header": "Yellow World!" } }),
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};
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const handleRequest = ({ method, url }) => {
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const handler =
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routeHandlers[`${method} ${url}`] ||
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(() => ({ statusCode: 404, data: "Not Found", headers: { "My-Header": "Not Found" } }));
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const { statusCode, data } = handler();
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const headers = { ...baseHeader, "Content-Length": Buffer.byteLength(data) };
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return { headers, statusCode, data };
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};
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server.listen(PORT, () => {
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console.log(`Server is listening at :${PORT}`);
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});

‎src/chapter_06.2/index.js‎

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const http = require("node:http");
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const PORT = 5255;
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class Router {
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constructor() {
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this.routes = {};
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}
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addRoute(method, path, handler) {
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this.routes[`${method} ${path}`] = handler;
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}
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handleRequest(request, response) {
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const { url, method } = request;
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const handler = this.routes[`${method} ${url}`];
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if (!handler) {
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return console.log("404 Not found");
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}
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handler(request, response);
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}
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printRoutes() {
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console.log(Object.entries(this.routes));
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}
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}
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const router = new Router();
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router.addRoute("GET", "/", function handleGetBasePath(req, res) {
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console.log("Hello from GET /");
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res.end();
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});
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router.addRoute("POST", "/", function handlePostBasePath(req, res) {
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console.log("Hello from POST /");
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res.end();
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});
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// Note: We're using an arrow function instead of a regular function now
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let server = http.createServer((req, res) => router.handleRequest(req, res));
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server.listen(PORT);

‎src/chapter_06.3/index.js‎

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const http = require("node:http");
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const PORT = 5255;
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const HTTP_METHODS = {
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GET: "GET",
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POST: "POST",
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PUT: "PUT",
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DELETE: "DELETE",
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PATCH: "PATCH",
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HEAD: "HEAD",
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OPTIONS: "OPTIONS",
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CONNECT: "CONNECT",
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TRACE: "TRACE",
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};
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class Router {
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constructor() {
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this.routes = {};
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}
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#addRoute(method, path, handler) {
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if (typeof path !== "string" || typeof handler !== "function") {
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throw new Error("Invalid argument types: path must be a string and handler must be a function");
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}
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this.routes[`${method} ${path}`] = handler;
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}
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handleRequest(request, response) {
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const { url, method } = request;
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const handler = this.routes[`${method} ${url}`];
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if (!handler) {
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return console.log("404 Not found");
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}
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handler(request, response);
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}
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get(path, handler) {
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this.#addRoute(HTTP_METHODS.GET, path, handler);
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}
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post(path, handler) {
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this.#addRoute(HTTP_METHODS.POST, path, handler);
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}
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put(path, handler) {
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this.#addRoute(HTTP_METHODS.PUT, path, handler);
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}
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delete(path, handler) {
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this.#addRoute(HTTP_METHODS.DELETE, path, handler);
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}
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patch(path, handler) {
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this.#addRoute(HTTP_METHODS.PATCH, path, handler);
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}
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head(path, handler) {
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this.#addRoute(HTTP_METHODS.HEAD, path, handler);
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}
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options(path, handler) {
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this.#addRoute(HTTP_METHODS.OPTIONS, path, handler);
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}
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connect(path, handler) {
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this.#addRoute(HTTP_METHODS.CONNECT, path, handler);
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}
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trace(path, handler) {
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this.#addRoute(HTTP_METHODS.TRACE, path, handler);
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}
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printRoutes() {
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console.log(Object.entries(this.routes));
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}
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}
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const router = new Router();
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router.get("/", function handleGetBasePath(req, res) {
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console.log("Hello from GET /");
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res.end();
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});
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router.post("/", function handlePostBasePath(req, res) {
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console.log("Hello from POST /");
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res.end();
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});
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// Note: We're using an arrow function instead of a regular function now
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let server = http.createServer((req, res) => router.handleRequest(req, res));
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server.listen(PORT);

‎src/chapter_07/challenge_1.js‎

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class TrieNode {
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isEndOfWord = false;
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children = new Map();
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}
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class Trie {
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constructor() {
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this.root = new TrieNode();
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}
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insert(word, node = this.root) {
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const wordLength = word.length;
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// Exit condition: If the word to insert is empty, terminate the recursion.
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if (wordLength === 0) return;
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for (let idx = 0; idx < wordLength; idx++) {
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let char = word[idx];
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// Check if the current node has a child node for the current character.
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if (!node.children.has(char)) {
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// If not, create a new TrieNode for this character and add it to the children of the current node.
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node.children.set(char, new TrieNode());
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}
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// Move to the child node corresponding to the current character.
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node = node.children.get(char);
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}
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node.isEndOfWord = true;
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}
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}

‎src/chapter_07/challenge_2.js‎

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class TrieNode {
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isEndOfWord = false;
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children = new Map();
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}
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class Trie {
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constructor() {
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this.root = new TrieNode();
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}
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search(word) {
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// Initialize 'currentNode' to the root node of the Trie.
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let currentNode = this.root;
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// Loop through each character in the input word.
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for (let index = 0; index < word.length; index++) {
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// Check if the current character exists as a child node
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// of the 'currentNode'.
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if (currentNode.children.has(word[index])) {
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// If it does, update 'currentNode' to this child node.
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currentNode = currentNode.children.get(word[index]);
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} else {
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// If it doesn't, the word is not in the Trie. Return false.
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return false;
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}
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}
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// After looping through all the characters, check if the 'currentNode'
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// marks the end of a word in the Trie.
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return currentNode.isEndOfWord;
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}
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insert(word, node = this.root) {
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const wordLength = word.length;
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if (wordLength === 0) return;
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for (let idx = 0; idx < wordLength; idx++) {
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let char = word[idx];
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if (!node.children.has(char)) {
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node.children.set(char, new TrieNode());
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}
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node = node.children.get(char);
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}
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node.isEndOfWord = true;
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}
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}

‎src/chapter_08/challenge_1.js‎

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class RouteNode {
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constructor() {
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// Create a Map to store children nodes
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this.children = new Map();
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// Initialize the handler to null
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this.handler = null;
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}
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}
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class TrieRouter {
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constructor() {
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// Create a root node upon TrieRouter instantiation
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this.root = new RouteNode();
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}
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addRoute(path, handler) {
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// Validate input types
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if (typeof path !== "string" || path[0] !== "/") throw new Error("Malformed path provided.");
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if (typeof handler !== "function") throw new Error("Handler should be a function");
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// Start at the root node of the Trie
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let currentNode = this.root;
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// Split the path into segments and filter out empty segments
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let routeParts = path.split("/").filter(Boolean);
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// Loop through all segments of the route
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for (let idx = 0; idx < routeParts.length; idx++) {
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const segment = routeParts[idx].toLowerCase();
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if (segment.includes(" ")) throw new Error("Malformed path parameter");
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// Attempt to find the next node in the Trie
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let childNode = currentNode.children.get(segment);
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// If the next node doesn't exist, create it
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if (!childNode) {
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childNode = new RouteNode();
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currentNode.children.set(segment, childNode);
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}
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// Move to the next node for the next iteration
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currentNode = childNode;
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}
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// Assign the handler to the last node
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currentNode.handler = handler;
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}
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printTree(node = this.root, indentation = 0) {
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const indent = "-".repeat(indentation);
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node.children.forEach((childNode, segment) => {
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console.log(`${indent}${segment}`);
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this.printTree(childNode, indentation + 1);
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});
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}
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}
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const trieRouter = new TrieRouter();
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function ref() {}
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trieRouter.addRoute("/home/", ref);
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trieRouter.addRoute("/user/status/play", function inline() {});
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trieRouter.printTree();

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