Function assert

src/core/assert/base.js:35–75

(
  sentinel,
  shouldBeTruthy,
  opt_message = 'Assertion failed',
  var_args
)

 * @throws {Error} when shouldBeTruthy is not truthy.
 */
export function assert(
  sentinel,
  shouldBeTruthy,
  opt_message = 'Assertion failed',
  var_args
) {
  if (shouldBeTruthy) {
    return /** @type {void} */ (shouldBeTruthy);
  }

  // Include the sentinel string if provided and not already present
  if (sentinel && opt_message.indexOf(sentinel) == -1) {
    opt_message += sentinel;
  }

  // Skip the first 3 arguments to isolate format params
  // const messageArgs = Array.prototype.slice.call(arguments, 3);
  // Index at which message args start
  let i = 3;

  // Substitute provided values into format string in message
  const splitMessage = opt_message.split('%s');
  let message = splitMessage.shift();
  const messageArray = [message];

  while (splitMessage.length) {
    const subValue = arguments[i++];
    const nextConstant = /** @type {NonNullable<*>} */ (splitMessage.shift());

    message += elementStringOrPassThru(subValue) + nextConstant;
    messageArray.push(subValue, nextConstant.trim());
  }

  const error = new Error(message);
  error.messageArray = remove(messageArray, (x) => x !== '');
  // __AMP_REPORT_ERROR is installed globally per window in the entry point in
  // AMP documents. It may not be present for Bento/Preact elements on non-AMP
  // pages.
  self.__AMP_REPORT_ERROR?.(error);
  throw error;
}

/**
 * Asserts types, backbone of `assertNumber`, `assertString`, etc.