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Angular 2+ multi-part form validation, how to check validity of single input

I have a form, and the form has multiple inputs that are all bound to different variables. Before submitting the form, I need to do validity checks, pristine checks, etc. For example, I want my submit button to be disabled if every part of the form is pristine, or if something is invalid.
Using Angular 5, I am trying to get access to the .pristine, .valid, and .invalid flags for each input field, but the values are either undefined or "cannot get .pristine of undefined".
I am able to get these flags on the entire form itself, but this doesn't help, because I want to know how to get it for each individual input.
Here is my current code (I've removed a number of my inputs to simplify the example).
<form #editDetailsForm="ngForm" name="editDetailsForm" >
<label for="name"> Name </label>
<input type="text" id="name" name="name" maxlength="40" [(ngModel)]="myName" required />
<label for="description"> Description </label>
<textarea id="description" name="description" maxlength="250" [(ngModel)]="myDescription" required ></textarea>
<button id="submit" type="button"
[disabled]="saveButtonDisabled(editDetailsForm.invalid, editDetailsForm.name.invalid, editDetailsForm.description.invalid)"
(click)="updateDetails()" >
Save
</button>
</form>
If you see, I bind disabled attribute on the Save button to saveButtonDisabled() function, where I want to pass in information about each input's validity. The first argument, editDetailsForm.invalid returns a true or false, but the other values return undefined.
How do I check validity of these individual inputs?
EDIT: I realize I can derive all of this info inside my component because all of the input values are bound. However, it'd be easier just to check a flag or two.

I'm not sure I totally understand what you want to do, but this is how you get access to the form controls .pristine, .invlaid
<input type="text" id="name" name="name" #name="ngModel" maxlength="40" [(ngModel)]="myName" required />
The #name="ngModel" sets a template reference to the FormControl angular creates
Then you should be able to do something like this:
<input type="text" id="name" name="name" #name="ngModel" maxlength="40" [(ngModel)]="myName" required />
<div *ngIf="name.pristine">
Name is Pristine
</div>
Just to clarify, the individual form fields bubble up to the form itself. So if any field has been touched, then the whole form will be pristine == false.

You can access the input controls using the .controls property, like:
<button id="submit" type="button"
[disabled]="editDetailsForm.controls.name?.invalid || editDetailsForm.controls.description?.invalid">

Created a stackblitz. https://stackblitz.com/edit/angular-5ir4k7
Added template reference variable for ngModel and validate using isValid.

Pass value in text if second option selected

I am trying to create a survey. The code looks like this:
<form ng-submit="passEngineer(engineer)">
<input type="radio" ng-model="engineer" ng-required="!engineer">Default
<input type="radio" ng-model="engineer" ng-required="!engineer">Custom
<input type="text" ng-model="engineer" ng-required="!engineer">
</form>
If First selected, it DOES pass it without issues. If Second selected, it SHOULD pass the value entered inside third input. How can I do that? Value in third input MUST be passed if second input selected. Tried many ways, can't really figure out.

I think you need to divide up how you're applying ng-model. You might make engineer an object in your controller and then change your markup like this:
<form ng-submit="passEngineer(engineer)">
<input name="engineer" type="radio" ng-model="engineer.isDefault">Default
<input name="engineer" type="radio" ng-model="engineer.isCustom">Custom
<input type="text" ng-model="engineer.customValue" ng-required="engineer.isCustom">
</form>

apply ng-required if another element is selected

I'm creating an optional part of a form. Once one of the two elements is selected (or text has been entered) the other is required but if there is no input for both these fields are not required. Can I accomplish this with ng-required? If not is there another way? Thanks for the help in advance!
Example Form

You can just do a ng-required with the other model as parameter:
<input ng-model="myFirstInput" />
<input ng-model="mySecondInput"
ng-required="myFirstInput" />
If the first input is filled in, myFirstInput will evaluate to truthy, so the second input will be required.
See this jsfiddle

you can use ng-required directive
<form name="myForm">
Click here to make the input field required:
<input type="checkbox" ng-model="myVar"><br><br>
<input name="myInput" ng-model="myInput" ng-required="myVar">
<h1 ng-if="!myForm.myInput.$valid">The input field cannot be empty</h1>
</form>

Does a ng-model work on ng-repeated fields?

I am using ng-repeat and I am various levels in such as:
`ul in output.content.innercontent` or `li in ul.content.innercontent`
my input looks like this:
<input id="{{input.key}}" name="{{input.label}}" type="text"
value="{{input.value}}" placeholder="{{input.defaultValue}}"
value="{{input.label}}"
class="form-control input-md" uib-tooltip="{{input.tooltip}}"
ng-if="input.type == 'input'">
On any one of those whenever a change happens and then an onBlur I want to make a call. Is this possible with ng-model & ng-model-options="{updateOn:'blur'}" with all these fields? The bind behavior I see online are mostly of an input to read-only field somewhere. Should I use ng-blur followed with a on("change") type of behavior?

try with
<input id="{{input.key}}" name="{{input.label}}" type="text"
ng-model="{{input.value}}" <!-- this -->
placeholder="{{input.defaultValue}}"
class="form-control input-md" uib-tooltip="{{input.tooltip}}"
ng-if="input.type == 'input'">
ng-model should do it
<input ng-model-options"{updateOn: 'blur'}"/>
==> This update the model only when user get outside the input
To call a function on-blur :
<input ng-blur="callThisFn()"/>

angularjs form input suggestions

I have a problem with a form in angularjs.
Example with classic html & php
<form name="myForm" action="post.php" method="post" autocomplete="on">
<input name="namename" type="text" />
<input name="email" type="text" />
<input name="submit" type="submit" value="submit" />
</form>
which works as expected. On the second visit, after i submitted the form for the first time, i just need to type the first letter and the input field will suggest something based on the first post.
The same form in angular.
<form name="myForm" ng-submit="test(user)" autocomplete="on">
<input name="name" type="text" ng-model="user.name" autocomplete="given-name" />
<input name="email" type="text" ng-model="user.email" />
<input name="submit" type="submit" value="submit" />
</form>
On the second visit here the form will suggest nothing at all, which is very irritating.
Is there any fix for that?
Example
thanks in advance.

That behaviour you're describing is done by the browser and is not guaranteed to work in all situations. It's actually quite easy to do in AngularJS; just keep track of a shared state object. This can be done in several ways, the most easiest by using the value provider like this:
// Create an injectable object with the name 'userInput'
angular.module('myApp').value('userInput', {});
Now inject this object in the controller that is handling the form like this:
angular.module('myApp').controller('MyController', function($scope, userInput) {
// Assign the state object to the scope so it's available for our view
$scope.user = userInput;
});
Render the form as you did and you'll see that the state of the form is kept. In fact, this is one of the hidden gems when programming with Angular since it allows you to keep very complex state information, which was previously pretty impractical.
Live demo can be found in this plunker.
Edit
One way to get the autocomplete to work is to maintain datalist elements. Just store the previous entered values in an array and use a ng-repeat to render all the options. Associate the input element with the datalist using the list attribute and you'r good to go.
<input list="nameHistory" type="text" ng-model="user.name" />
<datalist id="nameHistory">
<option ng-repeat="item in userHistory.name" value="{{ item }}"></option>
</datalist>
Live demo can be found in this plunker.

Just add to the input tag this attribute autocomplete="off"