invariant.js

/**
 * Copyright (c) 2013-present, Facebook, Inc.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * 
 */
'use strict';

var validateFormat = process.env.NODE_ENV !== "production" ? function (format) {} : function (format) {
  if (format === undefined) {
    throw new Error('invariant(...): Second argument must be a string.');
  }
};
/**
 * Use invariant() to assert state which your program assumes to be true.
 *
 * Provide sprintf-style format (only %s is supported) and arguments to provide
 * information about what broke and what you were expecting.
 *
 * The invariant message will be stripped in production, but the invariant will
 * remain to ensure logic does not differ in production.
 */

function invariant(condition, format) {
  for (var _len = arguments.length, args = new Array(_len > 2 ? _len - 2 : 0), _key = 2; _key < _len; _key++) {
    args[_key - 2] = arguments[_key];
  }

  validateFormat(format);

  if (!condition) {
    var error;

    if (format === undefined) {
      error = new Error('Minified exception occurred; use the non-minified dev environment ' + 'for the full error message and additional helpful warnings.');
    } else {
      var argIndex = 0;
      error = new Error(format.replace(/%s/g, function () {
        return String(args[argIndex++]);
      }));
      error.name = 'Invariant Violation';
    }

    error.framesToPop = 1; // Skip invariant's own stack frame.

    throw error;
  }
}

module.exports = invariant;