/**

* Copyright 2013-2014 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.

*

* @providesModule emptyFunction

*/

var copyProperties = require('copyProperties');

function makeEmptyFunction(arg) {

return function() {

return arg;

};

}

/**

* This function accepts and discards inputs; it has no side effects. This is

* primarily useful idiomatically for overridable function endpoints which

* always need to be callable, since JS lacks a null-call idiom ala Cocoa.

*/

function emptyFunction() {}

copyProperties(emptyFunction, {

thatReturns: makeEmptyFunction,

thatReturnsFalse: makeEmptyFunction(false),

thatReturnsTrue: makeEmptyFunction(true),

thatReturnsNull: makeEmptyFunction(null),

thatReturnsThis: function() { return this; },

thatReturnsArgument: function(arg) { return arg; }

});

module.exports = emptyFunction;