@klippa/ngx-enhancy-forms

NgxEnhancyForms

Enhancy Forms is the forms framework used for klippa frontend applications.

Known Issues:

• ngx-date-fns-adapter is not compatible with Angular 12. The date picker can be used, but cannot be internationalised.

How to install

Install using npm/yarn:

$ yarn add @klippa/ngx-enhancy-forms

Import the NgxEnhancyFormsModule into your module.

// my.module.js
/* ... */
import {NgxEnhancyFormsModule} from "@klippa/ngx-enhancy-forms";

@NgModule({
	declarations: [/* ... */],
	imports: [
		/* ... */,
		NgxEnhancyFormsModule,
	],

	exports: [
		/* ... */
		NgxEnhancyFormsModule, // Export it if you wish to use it in parent modules.
	],
})
export class MyModule {
}

Usage

Example form

<klp-form>
	<klp-form-element caption="Username">
		<klp-form-text-input formControlName='username'></klp-form-text-input>
	</klp-form-element>
	<klp-form-element caption="Password">
		<klp-form-password-field formControlName="password"></klp-form-password-field>
	</klp-form-element>
	<klp-form-submit-button fullWidth [submitCallback]="onSubmit">
		Login
	</klp-form-submit-button>
</klp-form>

@Component({
	selector: 'app-login-form',
	templateUrl: './login-form.component.html',
	styleUrls: ['./login-form.component.scss'],
})
export class LoginFormComponent {
	loginForm: FormGroup = this.fb.group({
		username: [null, Validators.required],
		password: [null, [Validators.required, Validators.minLength(8)]],
	});

	constructor( private fb: FormBuilder ) {}

	/** onSubmit must be a lambda function **/
	onSubmit = (value: any): Promise<void> => console.log(value);
}

Notable elements and features

<klp-form-submit-button>

The submitCallback is an input rather than a output. As such it must be a lambda function to maintain the correct scope.

Providing alternative error messages

The <klp-form-element> uses some default error messages for the internal validations. If you wish to use different messages, for example if you wish to translate them, you can do so by providing FORM_ERROR_MESSAGES somewhere in your application.

The FORM_ERROR_MESSAGES should be of type CustomErrorMessages as exported from types.ts.

The min, max, minLength, and maxLength messages will substitute %min%, %max%, %minLength%, and %maxLength% with their respective limits.

Here is an example of how you might provide translations for the example login form:

@Component({
	selector: 'app-login-form',
	templateUrl: './login-form.component.html',
	styleUrls: ['./login-form.component.scss'],
	providers: [
		{
			provide: FORM_ERROR_MESSAGES,
			deps: [TranslateService],
			useFactory: (translate: TranslateService) => {
				return {
					min: () => translate.instant(_("use a number larger than %min%")),
					/* ... */
				};
			},
		},
	],
})
export class LoginFormComponent {
 /* ... */
}

Providing locale preferences for the date picker

The DatePicker uses the @Angular/material date picker, but uses standard Dates internally so is only compatible with DateAdapters that also use Date.

Angular 10/11

For Angular 10 and 11, the Date restriction means that only the MatNativeDateAdapter or a custom adapter such as NgxMatDatefnsDateAdapter can be used. The former provides no localization capabilities and so is not very useful.

Here is an example of how to provide a customised NgxMatDatefnsDateAdapter that accepts multiple date formats for input

// custom DateAdapter
class MultiParseDateFnsDateAdapter extends NgxDateFnsDateAdapter {
	// override the parse function to take arrays of parseFormats and try each in turn.
	parse(value: any, parseFormat: any) {
		if (typeof value === 'string') {
			if (value.length === 0) {
				return null;
			}
			// replace all '/' and '.' with '-' for locales that use '/' or '.' seperated dates.
			value = value.replace(/[\/.]/g, '-');
		}
		if (Array.isArray(parseFormat)) {
			for (const format of parseFormat) {
				if (isMatch(value, format)) {
					return super.parse(value, format);
				}
			}
		}
		return null;
	}
}

git

@Component({
	selector: 'app-login-form',
	templateUrl: './login-form.component.html',
	styleUrls: ['./login-form.component.scss'],
	providers: [
		{ provide: DateAdapter, useClass: MultiParseDateFnsDateAdapter, deps: [MAT_DATE_LOCALE] },
		{
			provide: KLP_DATE_FORMATS,
			useValue: (format?: string) => { // format is the format provided as an input to the date field.
				const preferred = format ?? 'dd-MM-yyyy';
				return {
					parse: { // formats to parse.
						// if the selected format fails to parse try all supported and all long locale formats.
						dateInput: [preferred, 'dd-MM-yyyy', 'MM-dd-yyyy', 'PP', 'PPP', 'PPPP'],
					},
					display: { // format to display.
						dateInput: preferred, // Display as prefered format.
						monthLabel: 'MMM', // Month label in the date picker.
						monthYearLabel: 'MMM yyyy', // month and year label in the date picker.
						dateA11yLabel: 'MMM dd, yyyy', // Accessability variant for screen readers etc.
						monthYearA11yLabel: 'MMMM yyyy', // same as above.
					},
				};
			},
		},
	],
})
export class LoginFormComponent {
    /** **/
}

Here we provide a function for KLP_DATE_FORMATS to the LoginFormComponent, you can also do this in a module for project wide config.

Angular 12

NgxMatDatefnsDateAdapter currently does not support Angular 12, so localization is not possible.

Angular 13

Angular 13 introduces a new date adapter, @angular/material-date-fns-adapter.

TODO: work out how to use the MatDateFnsAdapter.