AngularJS Type Properties Guide
ng-app directive defines an AngularJS application. ng-controller directive defines an application controller. The novalidate attribute is not required in your application, but you need to use it in AngularJS forms to override standard HTML5 validation.
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Primarily every single single web application being created around gets inputs from its users. Perhaps it is got a comment feed having a handful of text boxes. Or perhaps it has some sort of calculator with various inputs and sliders. Certainly, there’s pretty much constantly the login page. Yes, the e mail and password are inputs too.
When working on web apps you are going to be handling inputs really a bit, and in that case, you ought to be effectively equipped to work with the right tools for the job. With AngularJS, those tools should contain the extensive assistance for forms, inputs and validations.
I’ve covered the fundamentals of writing types just before, but within this post I’d like to point out how Angular’s types have a couple of magic properties which might be worth recognizing, since they could spare you some bugs and code!
Very first Factors First: Finding Access for the Type
Forms in AngularJS have particular properties, but how specifically are you currently meant to have access to these types? The trick should be to name the type. When deliver a name for the forms, AngularJS will automatically expose it under that name inside your scope.
As an example, say that we have this as part of the template of a element with $ctrl as its controller-as name:
Setting the name to $ctrl.exampleForm implies that inside the template we can get access for the kind, basically by using $ctrl.exampleForm. It may also be accessed from the controller’s code, using this.exampleForm.
Now that we know how to have access for the type, let’s get started making use of it!
Testing No matter whether the User Has Interacted Using the Form
A very widespread use case could be the have to have to display particular error messages or assistance recommendations only soon after the user has began changing values within the type (or hasn’t started but).
To perform just that, types in AngularJS come supplied with two handy boolean properties, $pristine and $dirty. These two booleans are often the damaging of your other (i.e. $pristine === !$dirty).
When the form is in its virgin state and also the user hasn’t changed something however, $pristine is set to true. As soon as the user has interacted together with the form’s inputs, $pristine is set to false and $dirty is true.
In case you will need to programmatically force the form back to its pristine state (e.g. the user clicked on reset, or soon after a thriving save), you are able to get in touch with $ctrl.exampleForm.$setPristine().
Display Issues Right after Kind Submission
Sometimes, we want type validations to only be displayed just after the user has clicked the save button, rather than altering as the user kinds or moves between fields.
In those cases, basically hiding validations till the form becomes $dirty won’t do, which is specifically why forms also have the handy $submitted property. This property gets set to true when the user has submitted the kind, even if the form is invalid.
Submitting a kind signifies clicking a button which has the attribute type="submit", or pressing Enter/Return inside an input.
AngularJS will not stop the type from getting submitted if it’s invalid, meaning your ng-submit callback is named. You need to produce confident not to act in case the kind is not inside a valid state.
Checking when the Form Is Valid
And just so that you can verify whether the kind is valid or not, forms come equipped using a handful of far more swanky properties.
1st of all are the $valid and $invalid couple. If $valid is true - go correct ahead. If $invalid is true - some thing is amiss.
In case the type is invalid, the form’s $error hash will include all the vital facts about which fields are invalid and for what validations.
But, there’s an additional state here, that is when both are undefined. This can be achievable when the kind has asynchronous validators. This means that it’s essential to test these are true or false and not only “falsy” (e.g. undefined or null).
You can also check no matter whether the type is at the moment pending, and see which in the validators are being processed, by accessing the $pending hash (that is structured similarly to $error).
There’s lots far more which can be written about forms and their inputs in AngularJS, so if you’d like to hear a lot more please subscribe under!
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Datum: 29.12.2019 - 06:22 Uhr
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