import createWrapper from './internal/createWrapper';

import replaceHolders from './internal/replaceHolders';

import rest from './rest';

/** Used to compose bitmasks for wrapper metadata. */

var BIND_FLAG = 1,

BIND_KEY_FLAG = 2,

PARTIAL_FLAG = 32;

/**

* Creates a function that invokes the method at `object[key]` and prepends

* any additional `_.bindKey` arguments to those provided to the bound function.

*

* This method differs from `_.bind` by allowing bound functions to reference

* methods that may be redefined or don't yet exist.

* See [Peter Michaux's article](http://peter.michaux.ca/articles/lazy-function-definition-pattern)

* for more details.

*

* The `_.bindKey.placeholder` value, which defaults to `_` in monolithic

* builds, may be used as a placeholder for partially applied arguments.

*

* @static

* @memberOf _

* @category Function

* @param {Object} object The object to invoke the method on.

* @param {string} key The key of the method.

* @param {...*} [partials] The arguments to be partially applied.

* @returns {Function} Returns the new bound function.

* @example

*

* var object = {

* 'user': 'fred',

* 'greet': function(greeting, punctuation) {

* return greeting + ' ' + this.user + punctuation;

* }

* };

*

* var bound = _.bindKey(object, 'greet', 'hi');

* bound('!');

* // => 'hi fred!'

*

* object.greet = function(greeting, punctuation) {

* return greeting + 'ya ' + this.user + punctuation;

* };

*

* bound('!');

* // => 'hiya fred!'

*

* // using placeholders

* var bound = _.bindKey(object, 'greet', _, '!');

* bound('hi');

* // => 'hiya fred!'

*/

var bindKey = rest(function(object, key, partials) {

var bitmask = BIND_FLAG | BIND_KEY_FLAG;

if (partials.length) {

var holders = replaceHolders(partials, bindKey.placeholder);

bitmask |= PARTIAL_FLAG;

}

return createWrapper(key, bitmask, object, partials, holders);

});

export default bindKey;