Playing with simply but highly-efficient DOM selections

dom.js

var dom = {

    toArray: function (nodes) {

        var array = [];

        if (nodes) {

            array = typeof nodes.length === 'number' ?
                    Array.prototype.slice.call(nodes) :
                    [nodes]

        }

        return array;

    },

    byId: function (id, context) {

        var start = context || document;

        return this.toArray(start.getElementById(id));

    },

    byClass: function (className, context) {

        var start = context || document;

        return this.toArray(start.getElementsByClassName(className));

    },

    byTag: function (tag, context) {

        var start = context || document;

        return this.toArray(start.getElementsByTagName(tag));

    },

    byQuery: function (query, context) {

        var start = context || document;

        return this.toArray(start.querySelectorAll(tag));

    },

    get: function (query, context) {

        var found = null,
            name  = query.slice(1);

        if (/^#\w+$/.test(query)) {
            found = this.byId(name, context);
        } else if (/^\.\w+$/.test(query)) {
            found = this.byClass(name, context);
        } else if (/^\w+$/.test(query)) {
            found = this.byTag(query, context);
        } else {
            found = this.byQuery(query, context);
        }

        return found;

    }

};

// Compare:
dom.toArray(document.getElementById('test'));
dom.toArray(document.getElementsByClassName('test'));
dom.toArray(document.getElementsByTagName('test'));
dom.toArray(document.querySelectorAll('test'));

dom.get('#test');
dom.get('.test');
dom.get('test');
dom.get('div#test');

// dom.toArray([native code]) should be faster than dom.get() but important is
// the comparison between dom.toArray(document.querySelectorAll()) and dom.get()