Can't Override request.url in beforeRequest hook

[kevbook]

Use case, we need to check and append token search-param because our some of our vendors use search parameters instead of headers. But request.url only has a getter.

[sindresorhus]

You can make a new request:

return new Request(newURL, request);

[kevbook]

Something like this?

import type { BeforeRequestHook } from 'ky';

/**
 * Round-robin helper to rotate headers or search params (e.g. for API keys)
 *
 * Usage:
 * const client = await ky.create(url, {
 *   hooks: { beforeRequest: [
 *     roundRobin('headers', [
 *       { 'key': 'API_KEY_1', 'client-id': 'CLIENT_ID_1' ...},
 *       { 'key': 'API_KEY_2', 'client-id': 'CLIENT_ID_2' ...},
 *       { 'key': 'API_KEY_3', 'client-id': 'CLIENT_ID_3' ...}
 *     ])
 *   ]}
 * });
 */
export const roundRobin = function (
  paramType: 'headers' | 'searchParams',
  requestParamsArr: Record<string, string>[]
) {
  // Validate that each object has non-empty string values
  requestParamsArr.forEach(function (params, index) {
    if (
      Object.entries(params).some(function ([_key, value]) {
        return typeof value !== 'string' || value.trim() === '';
      })
    ) {
      throw new Error(`Request params at index ${index} contains non-string value`);
    }
  });

  const requestParamsLen = requestParamsArr.length;
  let state = 0; // Keeps track of which header set to use next

  return function (request) {
    // Get the current set of search params based on the state
    const currentParams = requestParamsArr[state] as Record<string, string>;

    // Apply each header in the current set
    if (paramType === 'headers') {
      for (const [key, value] of Object.entries(currentParams)) {
        request.headers.set(key, value);
      }

      // Move to the next header set in the array, loop back when at the end
      state = (state + 1) % requestParamsLen;
    } else if (paramType === 'searchParams') {
      const url = new URL(request.url);
      for (const [key, value] of Object.entries(currentParams)) {
        url.searchParams.set(key, value);
      }
      // Move to the next header set in the array, loop back when at the end
      state = (state + 1) % requestParamsLen;
      // console.log('===================', url);
      new Request(url, request);
    }
  } satisfies BeforeRequestHook;
};