packages/fbjs/src/__forks__/warning.js

/**
 * Copyright (c) 2014-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.
 *
 * @providesModule warning
 */

'use strict';

var emptyFunction = require('emptyFunction');

/**
 * Similar to invariant but only logs a warning if the condition is not met.
 * This can be used to log issues in development environments in critical
 * paths. Removing the logging code for production environments will keep the
 * same logic and follow the same code paths.
 */


function printWarning(format, ...args) {
  var argIndex = 0;
  var message = 'Warning: ' + format.replace(/%s/g, () => args[argIndex++]);
  if (typeof console !== 'undefined') {
    console.error(message);
  }
  try {
    // --- Welcome to debugging React ---
    // This error was thrown as a convenience so that you can use this stack
    // to find the callsite that caused this warning to fire.
    throw new Error(message);
  } catch (x) {}
}

var warning = __DEV__
  ? function(condition, format, ...args) {
      if (format === undefined) {
        throw new Error(
          '`warning(condition, format, ...args)` requires a warning ' +
          'message argument'
        );
      }
      if (!condition) {
        printWarning(format, ...args);
      }
    }
  : emptyFunction;

module.exports = warning;