fetch() operations

network.js

export class NetworkError extends Error {
  /**
   * @param {string} message
   * @param {number} status
   */
  constructor(message, status) {
    super();
    this.status = status;
  }
}

/** @type {(error: Error|NetworkError|any) => void} */
let errorHandler = null;

/**
 * @param {(error: Error|NetworkError|any) => Promise<any>} fn
 * @return {void}
 */
export function setDefaultErrorHandler(fn) {
  errorHandler = fn;
}

/**
 * @param {Error|NetworkError|any} error
 * @return {void}
 */
export function onPostError(error) {
  if (errorHandler) {
    errorHandler(error);
    return;
  }
  throw error;
}

/**
 * @param {string} url
 * @param {Object=} data
 * @param {Object} options
 * @param {number=} options.timeout Timeout in milliseconds
 * @param {string=} options.format response format
 * @param {boolean=} options.credentials response format
 * @param {Object<string,string>=} options.headers headers
 * @return {Promise<any>}
 */
export function postJson(url, data = {}, options = { timeout: 60000, format: 'json', headers: {} }) {
  /** @type {RequestInit} */
  const fetchOptions = {
    method: 'POST',
    credentials: options.credentials === false ? 'omit' : 'include',
    mode: 'cors',
    headers: {
      'Content-Type': 'application/json',
      ...options.headers,
    },
    body: JSON.stringify(data),
  };
  const promise = fetch(url, fetchOptions).then((response) => {
    if (response.status >= 400) {
      const err = new NetworkError(response.statusText, response.status);
      err.status = response.status;
      throw err;
    }
    if (response.status === 200) {
      if (options.format === 'string') {
        return response.text();
      }
      return response.json();
    }
    if (response.status === 204) {
      if (options.format === 'string') {
        return '';
      }
      return {};
    }
    // No content
    return null;
  });
  if (options.timeout) {
    return timeoutPromise(options.timeout, promise);
  }
  return promise;
}