I created an Angular Directive, that uses CSS selectors to automatically trim inputs in my application, it looks like so...
import { Directive, HostListener, forwardRef } from '@angular/core';
import { DefaultValueAccessor, NG_VALUE_ACCESSOR } from '@angular/forms';
export const TRIM_VALUE_ACCESSOR: any = {
provide: NG_VALUE_ACCESSOR,
useExisting: forwardRef(() => TrimInputDirective),
multi: true
};
/**
* The trim accessor for writing trimmed value and listening to changes that is
* used by the {@link NgModel}, {@link FormControlDirective}, and
* {@link FormControlName} directives.
*/
/* tslint:disable */
@Directive({
selector: `
input
:not([type=checkbox])
:not([type=radio])
:not([type=password])
:not([readonly])
:not(.ng-trim-ignore)
[formControlName],
input
:not([type=checkbox])
:not([type=radio])
:not([type=password])
:not([readonly])
:not(.ng-trim-ignore)
[formControl],
input
:not([type=checkbox])
:not([type=radio])
:not([type=password])
:not([readonly])
:not(.ng-trim-ignore)
[ngModel],
textarea
:not([readonly])
:not(.ng-trim-ignore)
[formControlName],
textarea
:not([readonly])
:not(.ng-trim-ignore)
[formControl],
textarea
:not([readonly])
:not(.ng-trim-ignore)[ngModel],
:not([readonly])
:not(.ng-trim-ignore)
[ngDefaultControl]'
`,
providers: [ TRIM_VALUE_ACCESSOR ]
})
/* tslint:enable */
export class TrimInputDirective extends DefaultValueAccessor {
protected _onTouched: any;
/**
* ngOnChange - Lifecycle hook that is called when any data-bound property of a directive changes.
* @param {string} val - trim value onChange.
*/
@HostListener('input', ['$event.target.value'])
public ngOnChange = (val: string) => {
this.onChange(val.trim());
}
/**
* applyTrim - trims the passed value
* @param {string} val - passed value.
*/
@HostListener('blur', ['$event.target.value'])
public applyTrim(val: string) {
this.writeValue(val.trim());
this._onTouched();
}
/**
* writeValue - trims the passed value
* @param {any} value - passed value.
*/
public writeValue(value: any): void {
if (typeof value === 'string') {
value = value.trim();
}
super.writeValue(value);
}
/**
* registerOnTouched Registers a callback function that should be called when the control receives a blur event.
* @param {function} fn - The user information.
*/
public registerOnTouched(fn: any): void {
this._onTouched = fn;
}
}
Now being a good developer I must right some unit tests... so I start to put a file together, here it is
import {Component} from '@angular/core';
import {async, ComponentFixture, TestBed} from '@angular/core/testing';
import {By} from '@angular/platform-browser';
import {TrimInputDirective} from './trim-input.directive';
import {expect} from 'chai';
@Component({
selector: 'my-directive-test-component',
template: ''
})
class TestComponent {
}
describe('Trim Directive', () => {
let fixture: ComponentFixture<TestComponent>;
let inputDebugElement: any;
let directive: TrimInputDirective;
beforeEach(async(() => {
TestBed.configureTestingModule({
declarations: [
TestComponent,
TrimInputDirective
],
providers: []
}).overrideComponent(TestComponent, {
set: {
template: '<input type=text>'
}
}).compileComponents().then(() => {
fixture = TestBed.createComponent(TestComponent);
fixture.detectChanges();
inputDebugElement = fixture.debugElement.query(By.css('input'));
directive = inputDebugElement.injector.get(TrimInputDirective);
});
}));
it('should trim the input', () => {
directive.ngOnChange(' 1234.56 ')
expect('1234.56').to.be('1234.56'); // I know this isn't the correct test... I will amend this
});
});
Now I wish to run my tests just to make sure that the setup in the spec file is correct, but I get the following error:
HeadlessChrome 0.0.0 (Mac OS X 10.12.6) Trim Directive before each
hook for should trim the input FAILED Uncaught (in promise): Error:
StaticInjectorError(DynamicTestModule)[TrimInputDirective]:
StaticInjectorError(Platform: core)[TrimInputDirective]:
NullInjectorError: No provider for TrimInputDirective! Error: StaticInjectorError(DynamicTestModule)[TrimInputDirective]:
I don't understand why I get this error, why do I have to provide the directive? I don't think this is necessary, also if I must provide what do I provide? Providing the actual directive doesn't work / resolve the error? I am very confused. If anyone can tell me how to resolve the issue or why I get it I would be most appreciative.
Please note that this is a legacy Angular App and was built before the
AngularCLI was available. So it is a little unorthodox (for example it isn't using Jasmin).
