// Extract route params (runtime parser to illustrate) function parseRoute(pattern: string, path: string) { const keys: string[] = []; const regex = new RegExp( "^" + pattern.replace(/:[^/]+/g, (m) => { keys.push(m.slice(1)); return "([^/]+)"; }) + "$" ); const m = path.match(regex); const out: Record<string, string> = {}; if (m) keys.forEach((k, i) => (out[k] = m[i + 1])); return out; } const params = parseRoute("/users/:userId/posts/:postId", "/users/123/posts/456"); console.log(JSON.stringify(params));