Redux style app

gistfile1.txt

// mock falcor Model
function Model(root, path) {
  this.root = root;
  this.path = path || [];
}

Model.prototype.bind = function(path) {
  return new Model(this.root, this.path.concat(path));
};

var appState = {
  entered: true,
  genres: {
    boundPath: ["genres"],
    paths: [
      [{from: 0, to: 1}, ["name", "length"]]
    ],
    entered: true,
    0: { 
      boundPath: [0],
      focused: true
    },
    1: { 
      boundPath: [1]
    }
  }
};


function id(x) { return x; };

function mapKeys(doc,
recurse, acc, props){
  if (doc == null || typeof doc !== "object") {
    return doc;
  }

  var copy = {};
  recurse = recurse || id;
  props = props || {};
      
  Object.
    keys(props).
    forEach(function(prop) {
      copy[prop] = props[prop];
    });

  var keys = Object.keys(doc);

  keys.forEach(function(key) {
    if (!(key in props)) {
      copy[key] = recurse(doc[key], acc);
    }
  });

  return copy;
};

var clearFocus = function clearFocus(doc, acc) {
  if(doc.entered || doc.focused) {
    return mapKeys(
      doc, 
      clearFocus,
      acc,
      { 
        entered: undefined, 
        focused: undefined 
      });
  }
  else {
    return doc;
  }
};



var setFocus = function setFocus(doc, path) {
  if (path.length === 0) 
    return mapKeys(
      doc, 
      null, 
      null, 
      { focused: true });

  var head = path[0];
  if (doc[head]) {
    var copy = mapKeys(doc, null, null, {entered: true });
    copy[head] = setFocus(copy[head], path.slice(1));
    return copy;
  }
  return doc;
};

/*

var getPaths = function getPaths(doc, acc) {
  var boundPath = acc.boundPath;
  var paths = acc.paths;

  if (doc.boundPath) {
    boundPath = boundPath.concat(doc.boundPath);
  }
  
  if (doc.paths) {
    paths = paths.concat(doc.paths.map(function(path) { return boundPath.concat(path)));
  }

  return mapKeys(
    doc, 
    clearFocus,
    {
      boundPath: boundPath,
      paths: paths 
    });
  }
};

*/

var getPaths = function getPaths(doc, acc) {
  var boundPath = acc.boundPath;
  var paths = acc.paths;

  if (doc.boundPath) {
    boundPath = boundPath.concat(doc.boundPath);
  }
  
  if (doc.paths) {
    paths = paths.concat(doc.paths.map(function(path) { return boundPath.concat(path)));
  }

  return mapKeys(
    doc, 
    clearFocus,
    {
      boundPath: boundPath,
      paths: paths 
    });
  }
};

var doc = clearFocus(appState);

document.write("<pre>" + JSON.stringify(setFocus(doc, ["genres", 1]), null, 4) + "</pre>");