bob-gray/solv

/* istanbul ignore if */
if (typeof define !== "function") {
    var define = require("amdefine")(module);
}

define(function (require) {
    "use strict";

    require("../class/shim");
    require("../object/merge");
    require("../array/from");

    var meta = require("../meta"),
        type = require("../type");

    meta({
        "name": "Function",
        "type": "class",
        "global": true
    });

    meta({
        "name": "defaultArgs",
        "shim": true,
        "description": "A higher order function that returns a new function that will call the original filling in default arguments where arguments are incomplete",
        "arguments": [{
            "name": "nArgs",
            "type": "any",
            "description": "Default values by argument position. Objects are merged. Arrays are not."
        }],
        "returns": "any"
    });

    Function.shim("defaultArgs", defaultArgs);

    function defaultArgs () {
        var fn = this,
            defaults = Array.from(arguments);

        return function () {
            var args = Array.from(arguments).reduce(split, {
                    withoutDefaults: [],
                    withDefaults: []
                }),
                defaultFilled = Object.merge.deep(
                    args.withoutDefaults,
                    defaults,
                    args.withDefaults
                );
            
            return fn.apply(this, defaultFilled);
        };

        function split (args, arg, index) {
            if (type.is("undefined", defaults[index])) {
                args.withoutDefaults[index] = arg;

            } else {
                args.withDefaults[index] = arg;
            }

            return args;
        }
    }
});