1var baseRest = require('./_baseRest'),
2    createWrap = require('./_createWrap'),
3    getHolder = require('./_getHolder'),
4    replaceHolders = require('./_replaceHolders');
5
6/** Used to compose bitmasks for function metadata. */
7var WRAP_BIND_FLAG = 1,
8    WRAP_PARTIAL_FLAG = 32;
9
10/**
11 * Creates a function that invokes `func` with the `this` binding of `thisArg`
12 * and `partials` prepended to the arguments it receives.
13 *
14 * The `_.bind.placeholder` value, which defaults to `_` in monolithic builds,
15 * may be used as a placeholder for partially applied arguments.
16 *
17 * **Note:** Unlike native `Function#bind`, this method doesn't set the "length"
18 * property of bound functions.
19 *
20 * @static
21 * @memberOf _
22 * @since 0.1.0
23 * @category Function
24 * @param {Function} func The function to bind.
25 * @param {*} thisArg The `this` binding of `func`.
26 * @param {...*} [partials] The arguments to be partially applied.
27 * @returns {Function} Returns the new bound function.
28 * @example
29 *
30 * function greet(greeting, punctuation) {
31 *   return greeting + ' ' + this.user + punctuation;
32 * }
33 *
34 * var object = { 'user': 'fred' };
35 *
36 * var bound = _.bind(greet, object, 'hi');
37 * bound('!');
38 * // => 'hi fred!'
39 *
40 * // Bound with placeholders.
41 * var bound = _.bind(greet, object, _, '!');
42 * bound('hi');
43 * // => 'hi fred!'
44 */
45var bind = baseRest(function(func, thisArg, partials) {
46  var bitmask = WRAP_BIND_FLAG;
47  if (partials.length) {
48    var holders = replaceHolders(partials, getHolder(bind));
49    bitmask |= WRAP_PARTIAL_FLAG;
50  }
51  return createWrap(func, bitmask, thisArg, partials, holders);
52});
53
54// Assign default placeholders.
55bind.placeholder = {};
56
57module.exports = bind;
58