index.js

/**
 * Copyright 2021 The AMP HTML Authors. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS-IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * Some exceptions (DOMException, namely) have read-only message.
 * @param {!Error} error
 * @return {!Error};
 */
export function duplicateErrorIfNecessary(error) {
  const messageProperty = Object.getOwnPropertyDescriptor(error, 'message');
  if (messageProperty?.writable) {
    return error;
  }

  const {message, stack} = error;
  const e = new Error(message);
  // Copy all the extraneous things we attach.
  for (const prop in error) {
    e[prop] = error[prop];
  }
  // Ensure these are copied.
  e.stack = stack;
  return e;
}

/**
 * @param {...*} var_args
 * @return {!Error}
 * @visibleForTesting
 */
export function createErrorVargs(var_args) {
  let error = null;
  let message = '';
  for (const arg of arguments) {
    if (arg instanceof Error && !error) {
      error = duplicateErrorIfNecessary(arg);
    } else {
      if (message) {
        message += ' ';
      }
      message += arg;
    }
  }

  if (!error) {
    error = new Error(message);
  } else if (message) {
    error.message = message + ': ' + error.message;
  }
  return error;
}

/**
 * Rethrows the error without terminating the current context. This preserves
 * whether the original error designation is a user error or a dev error.
 * @param {...*} var_args
 */
export function rethrowAsync(var_args) {
  const error = createErrorVargs.apply(null, arguments);
  setTimeout(() => {
    // __AMP_REPORT_ERROR is installed globally per window in the entry point.
    // It may not exist for Bento components without the runtime.
    self.__AMP_REPORT_ERROR?.(error);
    throw error;
  });
}

/**
 * Executes the provided callback in a try/catch and rethrows any errors
 * asynchronously.
 *
 * @param {function(...*):T} callback
 * @param {...*} args
 * @return {T}
 * @template T
 */
export function tryCallback(callback, ...args) {
  try {
    return callback.apply(null, args);
  } catch (e) {
    rethrowAsync(e);
  }
}