Tester for a validateRoutePath function that I released to nestjs/swagger.

test-validateRoutePath.js

const isUndefined = obj => typeof obj === 'undefined'
const validatePath = path => path.charAt(0) !== '/' ? '/' + path : path;
const pathToRegexp = require('path-to-regexp');

function validateRoutePathNew(path) {
  if (isUndefined(path)) {
      return '';
    }
  let pathWithParams = '';
  for (const item of pathToRegexp.parse(path)) {
    if (typeof item === 'string') {
      pathWithParams += item;
    } else {
      pathWithParams += `${item.prefix}{${item.name}}`;
    }
  }
  return pathWithParams === '/' ? '' : validatePath(pathWithParams);
}
function validateRoutePathOld(path) {
  if (isUndefined(path)) {
    return '';
  }
  const pathWithParams = path.replace(/([:].*?[^\/]*)/g, str => {
    str = str.replace(/\(.*\)$/, ''); // remove any regex in the param
    return `{${str.slice(1, str.length)}}`;
  });
  return pathWithParams === '/' ? '' : validatePath(pathWithParams);
}

const tests = [
  "/hi/:hows/:it/:goin",
  "sorry/you/couldnt/:get.:through",
  "please/leave/your/name",
  "/",
  "and/",
  "/your/:number(\\d+)",
  "",
  "/and/we'll/:get.:back/:to/:you"
]

function run(name, fn) {
  console.log('# ' + name );
  const prefixWidth = tests.map(x => x.length).reduce((x, y) => Math.max(x, y), -1) + 6;
  for (const t of tests) {
    let line = '  ' + t;
    while (line.length < prefixWidth)
      line += ' ';
    line += '=>   '
    line += fn(t);
    console.log(line)
  }
  console.log();
}

run('Old Style', validateRoutePathOld);
run('New Style', validateRoutePathNew);