ddd-form

Decorator Driven Dynamic Forms version 10.0.9-a

Opinionated way to create dynamic forms with no json , no inheritance just use decorators

issues fixed in this version

1. nested forms now can have its own css class via meta attribute class and also its own legen class

2. fixed patch method to use partial objects for nested attributes and also patches disabled fields

3. added hasChildren(): boolean method to the interface InputNode dont worry it will not affect any working code.

4. enableFn now works on intial values , before this fix value must change to make the effect

5. validation error message works now in production

6. exported ErrorMessagePipe to make customization easier.

7. export form context annotations

8. form initial value only takes first change solved

9. disabled attribute doesn't work

10. exported date validations

11. field override in some context affects other contexts

Project Goals

0. use one consistent strategy for creating form some thing that can be used as specification like other frame works ex JPA java persistence API just an API that tells how to do data base related operation

1. create annotation driven dynamic form no more inheritance I think metadata must be placed in decorators not as class attributes

2. take most used defaults into considerations we can't create something that abstracts every thing, but we can make some things that really fits in the common problems and repeated tasks

3. the ability to create forms fast forms that search, forms that perform CRUD operations is a perfect example

4. intuitive API I think creating something great means we can use it easily and really understand it without many efforts

5. composable forms you can nest forms to any level to make form creation easily

6. supports complex layouts by using grids

7. opinionated based on commons and defaults

8. flexibility to customize UI , UI that uou want , UI can change but forms, inputs, validations are concepts that are the same.

Dependencies

Angular version	bootstrap Version
12.2.15	5.1.3

Features

• [x] validation

• [x] cross validation

• [x] async validation

• [x] customized error messages and string interpolation can be used some text...${var} some text ..

• [x] decorator driven

• [x] supports composition of forms

• [x] responsive relies on bootstrap5

• [x] layout management based on bootstrap5 grid

• [x] theming you can override css classes and styles

• [x] UI customization you can add your own templates or even your components for customized inputs

• [ ] internationalization is not supported yet

Supported Controls

• [x] text control
• [x] number control
• [x] date control
• [x] single select control
• [x] check boxes
• [x] radio buttons
• [ ] text area not supported yet
• [ ] multiple select is not supported yet
• [ ] range is not supported yet

Repositories

source on github , npm package

Install

Note that: library is under active development so some API may change. please use each version documentation to use the library. your opinions are appreciated

install boot strap if you don't have itnpm i bootstrap and add it in styles npm i ddd-form

[npm install decorator-driven-dynamic-forms --save]: # after that add its styles from decorator-driven-dynamic-form/assests/styles/styles.css to your angular app

contents

1. how to use
2. validation demo
3. Cross Validation demo
4. AsyncValidation demo
5. UI Customization demo
6. API summary
7. classes
8. decorators
9. directives

How To Use?

is step by step demonstration of common use cases

we will model book and author models where book refers to an author

1. import the DecoratorDrivenDynamicFormsModule and HttpClientModule into your app

import { DynamicFormModule } from "decorator-driven-dynamic-forms.module";

@NgModule({
  declarations: [AppComponent],
  imports: [
    BrowserModule,
    HttpClientModule,
    DynamicFormModule.register([Author, Book]),
  ], // register for entities in the system to be ready for injection
  providers: [],
  bootstrap: [AppComponent],
})
export class AppModule {}

2. create form model classes

author class is turned into form entity by using decorators and each field is mapped to an input based on the annotation and we provide meta data to the view.

we can control layout using width width: 4 layout is managed by bootstrap5 grid and each input is column and the whole form is a row any nested forms will take column and creates row as container for each input it has. which provides flexibility in layout break points are managed till now by the form

@FormEntity({ name: "Author" })
export class Author {
  @TextInput({
    id: "name",
    name: "name",
    type: "text",
    placeHolder: "name",
    width: 4,
  })
  name: string = "Adam";

  @NumberInput({
    id: "age",
    name: "age",
    width: 4,
  })
  age: number = 28;

  @CheckboxInput({
    id: "married",
    name: "married",
    label: "married",
    width: 4,
  })
  married: boolean = false;

  @RadioGroupInput({
    bindLabel: "description",
    bindValue: null,
    inputWidth: 3,
    dataSource: [
      { id: 1, description: "male" },
      { id: 2, description: "female" },
      { id: 3, description: "else!" },
    ],
    id: "gender",
    legend: "Gender",
    name: "gender",
  })
  gender: any = null;
}

book is related to author (each time we enter a book we enter its author data this is not real world scenario, but this example shows how to compose forms using already existing forms) we can add buttons to the form and configure its styles standard form actions are supported natively, non standard buttons can be added to it will be explained later.

@Submit({ id: "submit", label: "ok" })
@FormEntity({ name: "Book" })
export class Book {
  @Required({ message: "isbn is mandatory" })
  @TextInput({
    id: "isbn",
    name: "isbn",
    type: "text",
    placeHolder: "ISBN",
    hint: "hello world hint!",
    width: 4,
  })
  isbn: string | null = null;

  @NumberInput({
    id: "price",
    name: "price",
    hint: "price cant be less than 1$",
    width: 4,
  })
  price: number | null = null;

  @DateInput({
    id: "publishDate",
    name: "publishDate",
    type: "date",
  })
  publishDate: string | null = null;

  @NestedFormEntity({
    legend: "Author",
    name: "author",
    declaredClass: Author,
    legendClass: "",
  })
  author: Author | null = null;

  @SelectInput({
    id: "genre",
    name: "genre",
    bindLabel: "description",
    bindValue: null,
    dataSource: [
      { id: 1, description: "funny" },
      { id: 2, description: "horror" },
      { id: 3, description: "sci" },
    ],
    compareWith: (a, b) => a == b,
    label: "genre",
  })
  genre: any = null;
}

3. create the entity and prepare parent component to handle the events here we use it directly in app component but we can use it in any other components

@Component({
  selector: "app-root",
  templateUrl: "./app.component.html",
  styleUrls: ["./app.component.css"],
  providers: [],
})
export class AppComponent implements OnInit {
  title = "dynamic-forms-driver";

  onSubmit($event: any) {
    console.log($event);
  }

  onClick($event: any) {
    console.log($event);
  }

  onChange($event: any) {
    console.log("new value", $event);
  }

  constructor() {}

  ngOnInit(): void {}
}

4. pass it the form entity to the dynamic-form-component

<d-form
    entityName="Book"
    (changeEvent)="onChange($event)"
    (submitEvent)="onSubmit($event)"
    (buttonClickEvent)="onClick($event)"
  >
</d-form>

5. Run ng s and see the result your self.

note we have two way binding between form entity and the UI form u see so if you set any value in the form entity it will be reflected in UI and any change in UI will be reflected in the entity so trythis.bookEntity.isbn = 'pla-pla' press Ctl+s and see

adding validation

in book class we can see the lines

@Required({message: "isbn is mandatory"})
@TextInput({
  id: "isbn",
  name: "isbn",
  type: "text",
  placeHolder: "ISBN",
  hint: "hello world hint!",
  width: 4,
})
isbn: string | null = null; // field isbn in book class now is required

which is used to make the field required we can add multiple validations on single field validations list

1. Required
2. Min
3. Max
4. MaxLength
5. MinLength
6. MinDate
7. MaxDate
8. RequiredTrue
9. Pattern

lets add some validation to the author set min age and name constrains

@FormEntity({ name: "Author" })
export class Author {
  @Required({ message: "author name is mandatory" })
  @TextInput({
    id: "name",
    name: "name",
    type: "text",
    placeHolder: "name",
    width: 4,
  })
  name: string = "Adam"; // default value

  @Min({ minValue: 1, message: "age cant be less than 1" })
  @NumberInput({
    id: "age",
    name: "age",
    width: 4,
  })
  age: number = 28;

  @CheckboxInput({
    id: "married",
    name: "married",
    label: "married",
    width: 4,
  })
  married: boolean = false;

  @RadioGroupInput({
    bindLabel: "description",
    bindValue: null,
    inputWidth: 3,
    dataSource: [
      { id: 1, description: "male" },
      { id: 2, description: "female" },
      { id: 3, description: "else!" },
    ],
    id: "gender",
    legend: "Gender",
    name: "gender",
  })
  gender: any = null;
}

another form of validation 'Cross Validation'

cross validation puts constrains across form fields like staring date, end date fields are constrained, some time you accept some combination of value only here you can use cross validation its used on the form entity

we will add date of birth and date of death of the author and if date of death is provided it must be > birth date lets add the block

@CrossValidation({
  errorName: 'dateOfDeath',
  effects: [
    {
      input: 'deathDate', // input name that is affected by that constrain
      message: 'death date cant be less than birth date', // error message to display if at that input if the constrain is violated.
    },
  ],
  validatorFn: (control: AbstractControl) => {
    const deathDate = control.get('deathDate');
    const birthDate = control.get('birthDate');
    if (new Date(deathDate?.value) <= new Date(birthDate?.value)) {
      deathDate?.setErrors({ expirationDate: true });
      return { dateOfDeath: true };
    }
    return null;
  },
})

now author class looks like

@CrossValidation({
  errorName: "dateOfDeath",
  effects: [
    {
      input: "deathDate", // input name that is affected by that constrain
      message: "death date cant be less than birth date", // error message to display if at that input if the constrain is violated.
    },
  ],
  validatorFn: (control: AbstractControl) => {
    // control represents form group that holds all the inputs
    const deathDate = control.get("deathDate");
    const birthDate = control.get("birthDate");
    if (new Date(deathDate?.value) <= new Date(birthDate?.value)) {
      deathDate?.setErrors({ dateOfDeath: true });
      return { dateOfDeath: true };
    }
    return null;
  },
})
@FormEntity({ name: "Author" })
export class Author {
  @Required({ message: "author name is mandatory" })
  @TextInput({
    id: "name",
    name: "name",
    type: "text",
    placeHolder: "name",
    width: 4,
  })
  name: string = "Adam"; // default value

  @Min({ minValue: 1, message: "age cant be less than 1" })
  @NumberInput({
    id: "age",
    name: "age",
    width: 4,
  })
  age: number = 28;

  @CheckboxInput({
    id: "married",
    name: "married",
    label: "married",
    width: 4,
  })
  married: boolean = false;

  @RadioGroupInput({
    bindLabel: "description",
    bindValue: null,
    inputWidth: 3,
    dataSource: [
      { id: 1, description: "male" },
      { id: 2, description: "female" },
      { id: 3, description: "else!" },
    ],
    id: "gender",
    legend: "Gender",
    name: "gender",
  })
  gender: any = null;

  @DateInput({
    id: "birth-date",
    name: "birthDate",
    type: "date",
    placeHolder: "birth date",
  })
  birthDate: Date | null = null;

  @DateInput({
    id: "death-date",
    name: "deathDate",
    type: "date",
    placeHolder: "death date",
  })
  deathDate: Date | null = null;
}

another form of validation AsyncValidation

used when we validate at backend server so the can be done too we will make sure isbn is unique before submitting the book form

we will add the block this is just demo for async validation but in real world scenario we will add a service that will call back end end point to validate this will explained later we just explore th API

 @AsyncValidation({
    errorName: "isbn",
    errorMessage: "ISBN must be unique",
    validator: (control: AbstractControl) => {
      return new Promise((resolve) => {
        setTimeout(() => {
          let err = { isbn: true };
          resolve(err);
        }, 10000);
      });
    },
  })

@Submit({ id: "submit", label: "ok" })
@FormEntity({ name: "Book", updateStrategy: UpdateStrategy.ON_PLUR })
export class Book {
  @AsyncValidation({
    errorName: "isbn",
    errorMessage: "ISBN must be unique",
    validator: (control: AbstractControl) => {
      return new Promise((resolve) => {
        setTimeout(() => {
          let err = { isbn: true };
          resolve(err);
        }, 10000);
      });
    },
  })
  @Required({ message: "isbn is mandatory" })
  @TextInput({
    id: "isbn",
    name: "isbn",
    type: "text",
    placeHolder: "ISBN",
    hint: "hello world hint!",
    width: 4,
  })
  isbn: string | null = null;

  @NumberInput({
    id: "price",
    name: "price",
    hint: "price cant be less than 1$",
    width: 4,
  })
  price: number | null = null;

  @DateInput({
    id: "publishDate",
    name: "publishDate",
    type: "date",
  })
  publishDate: string | null = null;

  @NestedFormEntity({
    legend: "Author",
    name: "author",
    declaredClass: Author,
    legendClass: "",
  })
  author: Author | null = null;

  @SelectInput({
    id: "genre",
    name: "genre",
    bindLabel: "description",
    bindValue: null,
    dataSource: [
      { id: 1, description: "funny" },
      { id: 2, description: "horror" },
      { id: 3, description: "sci" },
    ],
    compareWith: (a, b) => a == b,
    label: "genre",
  })
  genre: any = null;
}

note we added @FormEntity({name:"Book", updateStrategy: UpdateStrategy.ON_PLUR }) its good for performance to change form update strategy to ON_PLUR or ON_SUBMIT available update strategies

1. ON_CHANGE // default
2. ON_PLUR
3. ON_SUBMIT

UI Customization

1. override CSS file provided
2. provide templates to customize form locally (per use) ex: let-inputNode provides inputNode to the developer to use input node is the building block of this lib

<div class="container">
  <d-form
    entityName="Book"
    (changeEvent)="onChange($event)"
    (submitEvent)="onSubmit($event)"
    (buttonClickEvent)="onClick($event)"
  >
    <ng-template dfInputTemplate [inputType]="'NUMBER'" let-inputNode>
      <label class="form-label">{{ inputNode.getProperty("label") }} </label>
      <input type="number" [formControl]="inputNode.getControl()" />
    </ng-template>
  </d-form>
</div>

export interface InputNode {
  setProperties(map: Map<string, any>): void;
  addProperty(key: string, value: any): void;
  getProperty(key: string): any;

  setControl(control: AbstractControl): void;
  getControl(): AbstractControl;

  setErrorMap(map: Map<string, string>): void;
  getError(key: string): string | undefined;
  addError(key: string, value: string): void;

  addChild(node: InputNode): void;
  addChildren(nodes: InputNode[]): void;
  getChildren(): InputNode[] | null;

  isValid(): boolean;
  inValid(): boolean;
  isPending(): boolean;
}

3. provide custom ui components exlets create rating component which is used to rate books

let create the component first use @DynamicFormInput({ inputType: "rating" }) to provide it for framework to be used as input

@DynamicFormInput({ inputType: "rating" })
@Component({
  selector: "app-rating.rating-component",
  templateUrl: "./rating.component.html",
  styleUrls: ["./rating.component.css"],
})
export class RatingComponent extends InputComponent implements OnInit {
  fullRate = 5;
  private valueChanged = false;

  constructor() {
    super();
  }

  ngOnInit(): void {
    if (this.getValue() == null) {
      // remember to always initialize variables to avoid null pointer exceptions
      // always do that in ngOnInit
      this.setValue(0);
    }
    this.fullRate =
      this.getInputNode().getProperty("fullRate") || this.fullRate;
    console.log("update on ", this.getInputNode().getControl().updateOn);
  }

  get ratingItems(): number[] {
    return new Array(this.fullRate);
  }

  onClick(i: number) {
    this.valueChanged = true;
    this.setValue(i + 1);
  }

  @HostListener("mouseleave", ["$event.target"])
  onPlur(target: any) {
    if (this.valueChanged) {
      this.commitChanges();
      this.valueChanged = false;
    }
  }
}

rating html

<label class="form-label d-form-label">rate</label>
<div class="rating-warapper form-control d-form-input">
  <span
    class="ratingStar"
    *ngFor="let ratingStar of ratingItems; let i = index"
    [ngClass]="{ 'bright-ratingStar': i < getValue() }"
    (click)="onClick(i)"
  >
    &#9733;
  </span>
</div>

rating css

.ratingStar {
  cursor: pointer;
  display: inline-block;
  font-size: 1.5em;
  color: #777;
}

.bright-ratingStar {
  color: gold;
  /* color: #0d6efd; */
  /* color: gainsboro; */
}

.dimmed-ratingStar {
  color: #777;
}

.rating-component {
  display: block;
}

.rating-warapper {
  max-width: fit-content !important;
}

.rating-warapper:hover {
  border-color: #0d6efd;
  box-shadow: var(--df-focus-box-shadow);
}

register custom component

import { DynamicFormModule } from "decorator-driven-dynamic-forms.module";

@NgModule({
  declarations: [AppComponent],
  imports: [
    BrowserModule,
    HttpClientModule,
    DynamicFormModule.register([Author, Book, RatingComponent]),
  ], // register for entities in the system to be ready for injection
  providers: [],
  bootstrap: [AppComponent],
})
export class AppModule {}

and in our book class mark input to use it as its input mapping

@Max({ maxValue: 10, message: 'ddfff' })
@Min({ minValue: 0, message: 'ddfff' })
@CustomInput({
  inputType: 'rating',
  id: 'rate',
  name: 'rate',
  fullRate: 10,
})
rate: number = 5

book class now looks like

@Submit({ id: "submit", label: "ok" })
@FormEntity({ name: "Book", updateStrategy: UpdateStrategy.ON_PLUR })
export class Book {
  @AsyncValidation({
    errorName: "isbn",
    errorMessage: "ISBN must be unique",
    validator: (control: AbstractControl) => {
      return new Promise((resolve) => {
        setTimeout(() => {
          let err = { isbn: true };
          resolve(err);
        }, 10000);
      });
    },
  })
  @Required({ message: "isbn is mandatory" })
  @TextInput({
    id: "isbn",
    name: "isbn",
    type: "text",
    placeHolder: "ISBN",
    hint: "hello world hint!",
    width: 4,
  })
  isbn: string | null = null;

  @NumberInput({
    id: "price",
    name: "price",
    hint: "price cant be less than 1$",
    width: 4,
    label: "price",
  })
  price: number | null = null;

  @DateInput({
    id: "publishDate",
    name: "publishDate",
    type: "date",
  })
  publishDate: string | null = null;

  @NestedFormEntity({
    legend: "Author",
    name: "author",
    declaredClass: Author,
    legendClass: "",
  })
  author: Author | null = null;

  @SelectInput({
    id: "genre",
    name: "genre",
    bindLabel: "description",
    bindValue: null,
    dataSource: [
      { id: 1, description: "funny" },
      { id: 2, description: "horror" },
      { id: 3, description: "sci" },
    ],
    compareWith: (a, b) => a == b,
    label: "genre",
  })
  genre: any = null;

  @Max({ maxValue: 10, message: "rate can't exceed 10" })
  @Min({ minValue: 0, message: "rate can't be negative" })
  @CustomInput({
    inputType: "rating",
    id: "rate",
    name: "rate",
    fullRate: 10,
  })
  rate: number = 5;
}

API summary

Component API

DynamicFormComponent API selector ddd-form

Input	type	description
entityName	string	name of the entity just provide entity name and it will be searched in the registered entities
[valueTransformer]	FormValueTransformer<any, any>	an interface if provided and object with that interface it will be used to transform form value based on transform method
[useContext]	string	used to provide string value that represents different uses of the same form can be used with @UseContext(ctx:string) to make some inputs appear in some context and not in other

Output	type	description
(submitEvent)	any	FormGroup value of the rendered form
(changeEvent)	any	FormGroup value after change
(buttonClickEvent)	{buttonId: string, formValue: any}	when added custom button to the form it will emit that object that contains button id and form value

Classes

FormValueTransformer

used to transform form value form T to V DTO

export interface FormValueTransformer<T, V> {
  transform(formValue: T): V;
}

FormController

used to control form by injecting instance from the component as ViewChild

<d-form entityName="Book" #bookForm></d-form>

@ViewChild('bookForm') formController: FormController;

export interface FormController {
  markAllAsTouched(): void;
  markAsTouched(path: string): void;

  markAsInvalid(
    path?: string,
    errConfig?: { errName: string; errMessage: string }
  ): void;

  markFieldAsInvalid(
    path: string,
    errConfig: { errName: string; errMessage: string }
  ): void;

  disable(path: string): void;
  enable(path: string): void;

  setReadonly(path: string): void;
  unsetReadonly(path: string): void;

  getRowValue(): any;
  getValue(): any;

  fireAction(id: string): void;
  reset(value?: any, emitEvent?: boolean): void;
  patch(value?: any, emitEvent?: boolean): void;
  getName(): string;
}

InputComponent

its just a class that you extend to add your own components as input components it has the following description use this methods to integrate your component to dynamic form

class InputComponent implements OnInit {
  private inputNode!: InputNode;
  protected value!: any;

  constructor() {}

  ngOnInit(): void {}

  public getInputNode(): InputNode;

  public initialize(input: InputNode): void;

  public setValue(val: any): void; // note this sets the value but doesn't update it

  public getValue(): any;

  public commitChanges(): void; // here update and validation happens

  private onChange(): void;
}

DynamicFormContextService

used to inject current form value if you want to know about it any time in your custom component

@Injectable()
export class DynamicFormContextService {
  private context: any;
  constructor() {}

  public setContext(ctx: any) {
    this.context = ctx;
  }

  public getContext() {
    return this.context;
  }
}

FormEntityProcessorService

used top process the annotations used by the library to generate input nodes you can use it to generate input nodes and write the full UI from scratch recommended if you like so

@Injectable()
export class FormEntityProcessorService {
  constructor(private injector: Injector);

  public process(formEntity: any): InputNode;

  private createContextualNode(
    entity: any,
    context: UseContext,
    parentProperties?: Map<string, any>
  ): InputNode;
}

Directives

InputTemplateDirective

used to register templates for input to customize per form good use case is login where u want to make inputs look different

example to use

<d-form
   entityName="Book"
    (changeEvent)="onChange($event)"
    (submitEvent)="onSubmit($event)"
    (buttonClickEvent)="onClick($event)"
  >
  <ng-template dfInputTemplate [inputType]="'NUMBER'" let-inputNode>
      <label>{{inputNode.getProperty('label')}}</label>
  </ng-template>
</d-form>

Directive({
  selector: "[dfInputTemplate]",
});
export class InputTemplateDirective {
  @Input("inputType") inputType!: string;
  constructor(private templateRef: TemplateRef<any>) {}

  public getInputType(): string;

  public getTemplateRef(): TemplateRef;
}

Decorators

@Id()

used to mark a field as and id field in admin library its used to construct URI that needs an id

@UseContext(ctx:string)

set context variable to form and used to make form reusable in many contexts, where we can specify what fields can appear to that context to increase usability

@ContextOverride({context: string, properties: object)

used to override attributes according to context some filed may be enabled in a context and disabled in another you may also specify other things related to that context

@FormEntity(param?:FormSpec)

to declare class as form model that can be used in dynamic from component param of type

export type FormSpec = {
  name: string;
  updateStrategy: UpdateStrategy;
};

update strategy of type

export enum UpdateStrategy {
  ON_CHANGE = "ON_CHANGE",
  ON_PLUR = "ON_PLUR",
  ON_SUBMIT = "ON_SUBMIT",
}

@NestedFormEntity(specs: NestedFormSpec)

to include FormEntity as field in another model param of type

export type NestedFormSpec = {
  legend: string;
  name: string;
  declaredClass: any;
  legendClass: string;
  width?: number;
};

name : is the form group name you give to these form declaredClass: in the class it self that you want to make it as field constructor legend if specified shows as legend of field set

@Reset(meta: NativeActionSpec)

to set reset button meta data like label or even it class

@Submit(meta: NativeActionSpec)

to set submit button meta data like label or even it class default class is btn btn-primary.

@Button(meta: NativeActionSpec)

to add a custom button to the form like cancel button good use case is in pop up with from and you can cancel or save

export type NativeActionSpec = {
  id: string;
  label: string;
  width?: number;
  class?: string;
  enableFn?: (ctx?: FormGroup) => boolean;
};

Fields Decorators:

1. @TextInput(specs: TextInputSpec)

2. @NumberInput(specs: NumberInputSpec)

3. @DateInput(specs: DateInputSpec)

4. @SelectInput(specs: SelectInputSpec)

5. @CheckboxInput(specs: CheckInputSpec)

6. @RadioGroupInput(specs: RadioButtonsSpec)

7. @CustomInput(specs: CustomInputSpec)

@DynamicFormInput({ inputType: string })

used to register components to be used in the form by custom input decorator

export interface InputSpec {
  name: string;
  id: string;
  label?: string;
  placeHolder?: string;
  width?: number;
  style?: string;
  class?: string;
  enableFn?: (formValue: any) => boolean;
  readonly?: boolean;
  hint?: string;
  [x: string]: any;
}

export interface TextInputSpec extends InputSpec {
  type: "text" | "password" | "email" | "url" | "tel";
}

export interface DateInputSpec extends InputSpec {
  type: "date" | "month" | "week" | "datetime-local";
}

export interface NumberInputSpec extends InputSpec {}

export interface SelectInputSpec extends InputSpec {
  bindLabel: string;
  bindValue: string | null;
  compareWith: (a: any, b: any) => boolean;
  dataSource: URL | any[] | Observable<any[]>;
  defaultValueIndex?: number; // sets the index of default value else the defualt is null
}

export interface CheckInputSpec extends InputSpec {}

export interface RadioButtonsSpec extends InputSpec {
  legend: string;
  bindLabel: string;
  bindValue: string | null;
  dataSource: URL | any[] | Observable<any[]>;
}
export interface CustomInputSpec extends InputSpec {
  inputType: string;
}

Validation Decorators

// some errors needs some value to be more meaningful like
// min length or maxlength or min max
// its meaningless to say date it larger than the max value
// but its good to say `value is larger than  ${max}`

// this string interpolation i simple at run time that string is interpolated by
// `ValidationError` so `${var}` `var` is replaced by the value that the key `var` has
// in the error object

// message can be parametrized ex: 'name cant be larger than  ${requiredLength} characters'
  @MaxLength({maxlength: number, message: string})

  @MinLength({minlength: number, message: string})

  @Required({ message: string })

  @Max({ maxValue: number, message:  string})//message can be parametrized 'age cant be more than ${max} years'

  @Min({ minValue: number, message: string})//message can be parametrized 'age cant be lass than ${min}'

  @MaxDate({ maxDate: str | Date, message:  string})

  @MinDate({ minDate: str | Date, message:  string})

  @RequiredTrue({ message: string })

  @Email({ message: string })

Cross Validation

used to validate form value taking relative relation between fields good use case is date form and date to where we want date from always be less than date to

@CrossValidation(spec: CrossValidationSpec)
type Effect = {
  input: string;
  message: string; // error message appears when error occurs it will appear on that input
};
export type CrossValidationSpec = {
  errorName: string;
  effects: Effect[];
  validatorFn: ValidatorFn;
};

Async validation

used to validate fields asynchronously

@AsyncValidation(specs: AsyncValidationSpec)

export interface InjectableAsyncValidatorProvider {
  provider: any; // class that is injectable that implements AsyncValidator interface
}
export type AsyncValidationSpec = {
  validator:
    | AsyncValidator // class that implements async validator interface and not injectable
    | AsyncValidatorFn
    | InjectableAsyncValidatorProvider; // injectable class that implements async validator interface
  errorMessage: string;
  errorName: string;
};

Notes:

any opinions are appreciated, any contributions are welcome thanks .

License

MIT