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/**
* Lo-Dash 2.4.1 (Custom Build) <http://lodash.com/>
* Build: `lodash modularize underscore exports="node" -o ./underscore/`
* Copyright 2012-2013 The Dojo Foundation <http://dojofoundation.org/>
* Based on Underscore.js 1.5.2 <http://underscorejs.org/LICENSE>
* Copyright 2009-2013 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
* Available under MIT license <http://lodash.com/license>
*/
var baseCreateCallback = require('../internals/baseCreateCallback'),
keys = require('../objects/keys'),
property = require('../utilities/property');
/**
* Produces a callback bound to an optional `thisArg`. If `func` is a property
* name the created callback will return the property value for a given element.
* If `func` is an object the created callback will return `true` for elements
* that contain the equivalent object properties, otherwise it will return `false`.
*
* @static
* @memberOf _
* @category Utilities
* @param {*} [func=identity] The value to convert to a callback.
* @param {*} [thisArg] The `this` binding of the created callback.
* @param {number} [argCount] The number of arguments the callback accepts.
* @returns {Function} Returns a callback function.
* @example
*
* var characters = [
* { 'name': 'barney', 'age': 36 },
* { 'name': 'fred', 'age': 40 }
* ];
*
* // wrap to create custom callback shorthands
* _.createCallback = _.wrap(_.createCallback, function(func, callback, thisArg) {
* var match = /^(.+?)__([gl]t)(.+)$/.exec(callback);
* return !match ? func(callback, thisArg) : function(object) {
* return match[2] == 'gt' ? object[match[1]] > match[3] : object[match[1]] < match[3];
* };
* });
*
* _.filter(characters, 'age__gt38');
* // => [{ 'name': 'fred', 'age': 40 }]
*/
function createCallback(func, thisArg, argCount) {
var type = typeof func;
if (func == null || type == 'function') {
return baseCreateCallback(func, thisArg, argCount);
}
// handle "_.pluck" style callback shorthands
if (type != 'object') {
return property(func);
}
var props = keys(func);
return function(object) {
var length = props.length,
result = false;
while (length--) {
if (!(result = object[props[length]] === func[props[length]])) {
break;
}
}
return result;
};
}
module.exports = createCallback;