warning.js.flow 1.32 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47
/**
 * 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';

declare var __DEV__: boolean;

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;