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AngularJS - Create a directive that uses ng-model and md-autocomplete

I am trying to create a directive for md-autocomplete. I tried using the answer provide by AngularJS - Create a directive that uses ng-model, but it does not work for me.
My CodePen is here: http://codepen.io/colbroth/pen/QyMaQX/?editors=101.
The code is based on the Angular material demo for autocomplete at https://material.angularjs.org/latest/demo/autocomplete. I have multiple pages, which need an autocomplete field to select a state. I do not want to repeat the code for each web page component.
state-directive takes an md-autocomplete input, I need demoCtrl.selected state to reflect the same value in both cases. But when I update the input element, the state-directive does not reflect this and vice versa.
<input ng-model="demoCtrl.selectedState">
<state-directive ng-model="demoCtrl.selectedState">...</state-directive>

You are on the right track. Your problem is that your model is a string - a primitive in javascript but a ngModel always needs to be an object if you want to avoid these kind of problems.
Scope inheritance is normally straightforward, and you often don't even need to know it is happening... until you try 2-way data binding (i.e., form elements, ng-model) to a primitive (e.g., number, string, boolean) defined on the parent scope from inside the child scope. It doesn't work the way most people expect it should work. What happens is that the child scope gets its own property that hides/shadows the parent property of the same name. This is not something AngularJS is doing – this is how JavaScript prototypal inheritance works. New AngularJS developers often do not realize that ng-repeat, ng-switch, ng-view and ng-include all create new child scopes, so the problem often shows up when these directives are involved. (See this example for a quick illustration of the problem.)
This issue with primitives can be easily avoided by following the "best practice" of always have a '.' in your ng-models.
Taken from Understanding-Scopes
It also links to this Youtube video - 3 minutes of well invested time
function DemoCtrl() {
var self = this;
self.state = {
selected: "Maine"
};
}
Fixed codepen

Angular -> ng-repeat filtered array variable

Below I will put link to my example in Plunker to show you my problem.
In ng-repeat I have used array(filtrowane) to store data from filter result, also I have added ng-change on input for showing the value of filtrowane.length in console. Variable filtrowane is defined in controller, and after typing something It`s showing different values in console and in the view, can you tell me why?
PS. run your web browser console and you will see the difference.
example Plunker

When you change value, first ng-change is called, then $digest starts which will update filtrowane.
If you use such notations:
item in filtrowane = (tablica | filter:search)
do not use filtrowane in controller. Html should be view, so you should not declare any variables there, which you use in model (js).
Look here: http://plnkr.co/edit/QAHlbuZqWX4szglvMP87?p=preview
This code does same as yours, but filtering is done in javascript. A bit more complicated, but things are more clear. (it is also better for big arrays)

Use ng-blur instead of ng-change
<input type="text" ng-model="search" ng-blur="sprawdzFiltr()">
This is due to the ng-change is probably executed before the filter is applied, so the old value will be taken.

ng-change using previous value

I have the following input
<input style="margin-left:24px;" id="numOfRows" class="setupInput" size="10"
ng-model="rowVal" ng-init="rowVal = gameCtrl.getNumOfRows()" ng-change="gameCtrl.setNumOfRows({{rowVal}})">
The issue I'm running into is when I change the value in the box it's always 1 behind.
EX: current value = 6
Changed value to 3 - nothing happens
Changed value to 2 - {{gameCtrl.getNumOfRows()}} returns 3
Why is it lagging 1 update behind?

You may have couple of issues here:
1) Do not use interpolation ({{}}) in the ng-change expression.
i.e Change
ng-change="gameCtrl.setNumOfRows({{rowVal}})"
to
ng-change="gameCtrl.setNumOfRows(rowVal)"
2) Do not use ng-init for initialization, that is what controller is for, use your controller to initialize the value of rowVal.
3) Make sure you do not have old version of angular which had issues with ng-change/ng-model syncronization.
4) Assuming you are using controller As syntax (and previous statement is wrong) always try to bind properties to the controller instance, i.e use gameCtrl.rowVal. (It could be wrong because it is not clear from the context of the question whether it really should belong to the controller instance or is it inside ng-repeat or something the created the child scope).

Data binding in directive isolated scope

I want to create a directive with isolated scope, but I'm not able to get it working.
jsFiddle
I want to isolate age model in a directive scope. I want to perform some business logic on that model and then set that model to parent binding. I hope the fiddle is explanatory.
I am also adding a button to the template which when clicked should invoke a submit function:
<button ng-click="submit()">click me</button>
It seems the button is working fine, but why is $scope.$watch() is not begin triggered? In a normal situation, if I change the view value it will automatically update the model value. But now it isn't.

$watch requires a dollar sign, and you pass either a function or a string that is evaluated on your scope, i.e.:
$scope.$watch('age', function(value) {
There are many more errors in your code, for instance you don't have a declared variable called 'age' so this line will reference window.age and give you an error because it is undefined, you need to say $scope.age I think:
age = age+10;
It just looks like your updated fiddle is a playground, hope these point you in the right direction. I'd recommend going through the egghead.io angular videos.

Strange knockout js select option binding issue

Does anybody have a minute to take a look at a puzzling problem I'm having with Knockout JS and binding select lists?
The person's favourite color should be selected in the list by calling value: favColorId in the select list, rather than with the function-based call of value: favColorId(), something very strange is going on here, I've never used () in the past, it's also causing some other weird issues where it won't recall the value into the span (so changing the selected item does nothing).. I have tried recreating a simple sample as best I can demonstrating the issue.
http://jsfiddle.net/goneale/ph8Jw/

I have included my mapDictToArray() function but it simply converts a
javascript object into a key-value JS array. I wouldn't think that is
contributing to the problem.
Actually, that was part of the problem. The function returns a JavaScript array, not an observable array and therefor can't be used properly by Knockout. I've made the following changes to your code:
// The "mapDictToArray" makes a normal JS array, not a ko.observableArray();
// You can't simply "merge" a JS array with an observableArray(); you'll need
// some extra functionality for that: ko.utils.arrayPushAll()
// viewModel.colors(mapDictToArray(dict));
ko.utils.arrayPushAll(viewModel.colors(), mapDictToArray(dict));
// Apply the bindings *after* you've added the contents to the "colors" observable, in order to
// get the correct selected value
ko.applyBindings(viewModel);
That should do the trick (with the correct HTML without the () )!
JSFiddle.
UPDATE
I thought about my solution, but something wasn't correct. The only thing that was correct, was the part that you need to apply the bindings after you've added the contents of the colors observable. This is your fiddle, with that part moved down.
This works in your case, but you'll need to use the arrayPushAll method when there is already data inside the observableArray. This method merges, while you overwrite it when not using it (example with data inside the observable).