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var baseCallback = require('../internal/baseCallback'),
isIterateeCall = require('../internal/isIterateeCall'),
isObjectLike = require('../internal/isObjectLike'),
matches = require('./matches');
/**
* Creates a function that invokes `func` with the `this` binding of `thisArg`
* and arguments of the created function. If `func` is a property name the
* created callback returns the property value for a given element. If `func`
* is an object the created callback returns `true` for elements that contain
* the equivalent object properties, otherwise it returns `false`.
*
* @static
* @memberOf _
* @alias iteratee
* @category Utility
* @param {*} [func=_.identity] The value to convert to a callback.
* @param {*} [thisArg] The `this` binding of `func`.
* @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
* @returns {Function} Returns the callback.
* @example
*
* var users = [
* { 'user': 'barney', 'age': 36 },
* { 'user': 'fred', 'age': 40 }
* ];
*
* // wrap to create custom callback shorthands
* _.callback = _.wrap(_.callback, function(callback, func, thisArg) {
* var match = /^(.+?)__([gl]t)(.+)$/.exec(func);
* if (!match) {
* return callback(func, thisArg);
* }
* return function(object) {
* return match[2] == 'gt'
* ? object[match[1]] > match[3]
* : object[match[1]] < match[3];
* };
* });
*
* _.filter(users, 'age__gt36');
* // => [{ 'user': 'fred', 'age': 40 }]
*/
function callback(func, thisArg, guard) {
if (guard && isIterateeCall(func, thisArg, guard)) {
thisArg = null;
}
return isObjectLike(func)
? matches(func)
: baseCallback(func, thisArg);
}
module.exports = callback;
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