gistfile1.js

/*global Immutable*/

var raw_urls = _.range(1, 5).map(function (i) {
    return {id: i, url: "url.com" + i, title: "Title of " + i, content: "Content of " + i};});


var some_map = _.object(_.map(raw_urls, function(item) {
    return [item.id, item];
}));

var state = Immutable.fromJS({
    urls: some_map,
    pageNo: 1,
    showDetail: false,
    chosenUrlId: null,
    canUndo: false
});

var undoStack = [];

var freezeState = function () {
    return JSON.stringify(state);
};

var pushToUndoStack = function () {
    if (undoStack.length == 0 || ! Immutable.is(state, undoStack[undoStack.length-1])) {
        var oldState = state;
        undoStack.push(oldState);
    }

    if (undoStack.length > 1) {
    setStateBang({'canUndo': true}, true);

}
};

pushToUndoStack();

var undo = function () {
    var previousState = undoStack.pop();

    if (previousState) {
        window.setStateBang(previousState, true);
    } else {
        window.setStateBang({canUndo: false}, true);
    }

};


var setStateBang = function (keyOrObject, dontSaveToUndoStack) {
    // Pass either a key-value or an object

    if (!dontSaveToUndoStack) {
        pushToUndoStack();
    }

    state = state.merge(Immutable.fromJS(keyOrObject));


    window.renderTopLevel();
}

/** @jsx React.DOM */


var renderTopLevel = function () {
    var stateAsJS = state.toJS();

    React.renderComponent(
            <OuterContainer
             urls={stateAsJS.urls} pageNo={stateAsJS.pageNo}
             showDetail={stateAsJS.showDetail}
             canUndo={stateAsJS.canUndo}
             chosenUrlId={stateAsJS.chosenUrlId}/>,
        document.body
    );


};


window.renderTopLevel();