react-router-component/lib/util/warning.js

Declarative router component for React

/**
 * Copyright 2014 Facebook, Inc.
 *
 * 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.
 */

"use strict";

/**
 * 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.
 */

var warning = function(){};

if ("production" !== process.env.NODE_ENV) {
  warning = function(condition, format ) {var args=Array.prototype.slice.call(arguments,2);
    if (format === undefined) {
      throw new Error(
        '`warning(condition, format, ...args)` requires a warning ' +
        'message argument'
      );
    }

    if (!condition) {
      var argIndex = 0;
      /*eslint no-console:0*/
      console.warn('Warning: ' + format.replace(/%s/g, function()  {return args[argIndex++];}));
    }
  };
}

module.exports = warning;