| /** Used as the `TypeError` message for "Functions" methods. */ |
| var FUNC_ERROR_TEXT = 'Expected a function'; |
| |
| /* Native method references for those with the same name as other `lodash` methods. */ |
| var nativeMax = Math.max; |
| |
| /** |
| * Creates a function that invokes `func` with the `this` binding of the |
| * created function and arguments from `start` and beyond provided as an array. |
| * |
| * **Note:** This method is based on the [rest parameter](https://developer.mozilla.org/Web/JavaScript/Reference/Functions/rest_parameters). |
| * |
| * @static |
| * @memberOf _ |
| * @category Function |
| * @param {Function} func The function to apply a rest parameter to. |
| * @param {number} [start=func.length-1] The start position of the rest parameter. |
| * @returns {Function} Returns the new function. |
| * @example |
| * |
| * var say = _.restParam(function(what, names) { |
| * return what + ' ' + _.initial(names).join(', ') + |
| * (_.size(names) > 1 ? ', & ' : '') + _.last(names); |
| * }); |
| * |
| * say('hello', 'fred', 'barney', 'pebbles'); |
| * // => 'hello fred, barney, & pebbles' |
| */ |
| function restParam(func, start) { |
| if (typeof func != 'function') { |
| throw new TypeError(FUNC_ERROR_TEXT); |
| } |
| start = nativeMax(start === undefined ? (func.length - 1) : (+start || 0), 0); |
| return function() { |
| var args = arguments, |
| index = -1, |
| length = nativeMax(args.length - start, 0), |
| rest = Array(length); |
| |
| while (++index < length) { |
| rest[index] = args[start + index]; |
| } |
| switch (start) { |
| case 0: return func.call(this, rest); |
| case 1: return func.call(this, args[0], rest); |
| case 2: return func.call(this, args[0], args[1], rest); |
| } |
| var otherArgs = Array(start + 1); |
| index = -1; |
| while (++index < start) { |
| otherArgs[index] = args[index]; |
| } |
| otherArgs[start] = rest; |
| return func.apply(this, otherArgs); |
| }; |
| } |
| |
| module.exports = restParam; |