ArrayModel.js

var ArrayModel = function(){};

ArrayModel.prototype = [];
_.extend(ArrayModel.prototype, {
    pointer: -1,
    next: function ()
    {
        if (!((this.pointer + 1) in this)) {return false;}
        this.pointer = this.pointer + 1;
        return this;
    },
    prev: function ()
    {
        if (!((this.pointer - 1) in this)) {return false;}
        this.pointer = this.pointer - 1;
        return this;
    },
    first: function ()
    {
        this.pointer = 0;
        return this;
    },
    last: function ()
    {
        this.pointer = this.length - 1;
        return this;
    },
    remove: function ()
    {
        return this.splice(this.pointer, 1)[0];
    },
    replace: function (arr)
    {
        return this.splice(this.pointer, 1, arr)[0];
    },
    insertAfter: function (arr)
    {
        this.pointer = this.pointer + 1;
        return this.splice(this.pointer, 0, arr);
    },
    swap: function (index_a, index_b)
    {
        if (this.length === 1) {return this;}
        this.splice(index_b, 1, this.splice(index_a, 1, this[index_b])[0]);
        return this;
    },
    set_pointer: function (index)
    {
        index = parseInt(index, 10) || 0;
        this.pointer = index;
        return this;
    },
    get: function ()
    {
        if ( typeof this[this.pointer] === 'function' ) {
            return this[this.pointer]();
        }
        return this[this.pointer];
    }
});

var screenplay = new ArrayModel();