Util for replacing params in a React router style url config

createPath.ts

/**
 * Builds a path from a template and replaces the params
 *
 * @function createPath
 * @param path The configured path (e.g. /foo/:bar)
 * @param params The param values you want to replace it with (e.g. \{bar: 'baz'\})
 * @param search Any query string values that you want to add
 * @category routing
 */
export const createPath = (
  path: string,
  params: { [key: string]: string } = {},
  search: string = '',
) =>
  path
    // first replace all params
    .replace(/:(\w+)/g, (match, param) => {
      if (typeof params[param] !== 'undefined') {
        return params[param] || '';
      }
      return match;
    })

    // remove unresolved optional parts
    .replace(/\/:(\w+)\?/g, () => '')

    // remove ? from resolved optional parts
    .replace(/([^:]+?)\?/g, (match, part) => part)

    // do we still have params left?
    .replace(/:(\w+)/g, (match, param) => {
      throw new Error(`Param "${param}" is missing in params ${params}, needed for '${path}'`);
    }) + search;