Async form handling the angular way.
If you've developed angular apps you know how difficult it is to handle errors after submitting a form. Common scenarios include:
- 500 errors with messages like
Sorry, an unkown error occured. Please try again. - 400 errors from input validation that were not caught in the UI.
Angular provides a great set of directives if your only concern is immediate validation in the UI; however, they fall short for anything else.
angular-async-form (namespaced af) fills this gap with the following
directives:
- afSubmit This is a direct replacement for
ngSubmit. It accepts an angular expression (similar tongSubmit), and in addition to$eventit also exposes a callback function (exposed ascb).cbis used to communicate with the rest of the directives listed herein. - afMessage Displays a form wide message.
- afControlGroup Groups a form control with a corresponding error message.
- afControl Adds a form control to a form control group.
- afControlMessage Adds a message to a form control group.
You can customize it's behavior with afConfig.
- Unobtrusive. Use
afControlMessagein concert withngMessagesto display known validation errors in the UI before submitting the form, and unkown errors from async operations after the form is submitted. - Allows you to handle errors after a form is submitted and display them to the user inside the form.
- If an error was returned for a control (like for input validation that wasn't
handled in the UI), the control must receive a
blurevent before setting it's validity again totrue. - Display form wide error messages.
- 100% asynchronous. May be used with or without HTTP calls.
- Versatile Directive API.
- Handles all input types I.E.
input[type=radio],input[type=checkbox],textaraetc.
The directives are used in concert as follows:
<!DOCTYPE html>
<html ng-app="myApp">
<head>
<style>
.error {color: red;}
</style>
</head>
<body ng-controller="AppCtrl">
<h1>Hello {{ user.firstName }}!</h1>
<form af-submit="doSomething($event, cb)" novalidate>
<div class="error" af-message>{{ message }}</div>
<div class="control-group" af-control-group>
<div class="error" af-control-message>{{ error }}</div>
<input
name="firstName"
ng-model="user.firstName"
af-control
required>
<!-- doSomething($event, cb) is called. It's up to doSomething to warn the
user by calling cb if errors occured in async operations. If no errors
occurred, then doSomething can do something else like hide the form and load
a new view. -->
<button type="submit">Submit</button>
</div>
</form>
<script src="https://code.angularjs.org/1.4.8/angular.js"></script>
<script src="angular-async-form.js"></script>
<script src="app.js"></script>
</body>
</html>| Restriction | Requires | Scope |
|---|---|---|
A |
form |
Parent Scope (afSubmit must equal an angular expression) |
Use afSubmit as a direct replacement for ngSubmit. In addition to the $event
object, a callback is exposed as cb. cb has the following signature:
function (message, errors)
-
message- A message to display in the form E.G.Sorry, an unknown error occurred. Please try again.. This can be a string or any data type if you wish to display multiple form wide messages. See afMessage. -
errors- An enum of strings corresponding to control messages E.G.{ firstName: 'First names must start with the letter J at 4\'oclock in the afternoon.', lastName: 'We could not accept this value at this time.' }
See afControlMessage.
| Restriction | Requires | Scope |
|---|---|---|
AE |
^^afSubmit |
Child Scope provides message |
Adds a message to the child scope of the element it is used on. The message is
provided by passing a value as the message parameter in the afSubmit callback
function.
| Restriction | Requires | Scope |
|---|---|---|
AE |
?^^afSubmit |
Parent Scope |
Groups a form control with a corresponding message. This allows error messages
passed to the errors parameter in afSubmit to apply to their intended
control, or group of controls in the case of radio buttons and checkboxes. Multiple afControls must have the same name.
| Restriction | Requires | Scope |
|---|---|---|
AE |
^^afControlGroup |
Child Scope provides error |
Adds a message to a form control group. If the control received an error via the
errors parameter to the callback in afSubmit then it will be provided in this
directive's scope.
| Restriction | Requires | Scope |
|---|---|---|
A |
^^afControlGroup, ngModel |
Parent Scope (name is a required attribute) |
Adds a form control to a form control group. The name attribute is used as the
key when supplying errors to the callback function in afSubmit. This directive
may be used any number of times within afControlGroup (I.E. with radio inputs).
If this directive does not exist within afControlGroup, then no error will
display in afControlMessage.
Errors must be resolved by triggering a blur event on the control; otherwise,
successive evaluations of afSubmit will be blocked.
You can customize angular-async-form by using afConfig.
A simple object with the following properties:
updateOn(defaults toblur change) Setting this to a different DOM event changes the event used to trigger the removal of messages displayed withafControlMessage.
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