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[FormBuilder](https://angular.io/api/forms/FormBuilder) + [class-transformer-global-storage](https://github.com/petrzjunior/class-transformer) + [class-validator-multi-lang](https://github.com/endykaufman/class-validator-multi-lang) = dynamic form group builder for [Angular](https://angular.io)

## Installation

```bash
npm i --save class-transformer-global-storage class-validator-multi-lang ngx-dynamic-form-builder
```

## BREAKING CHANGE !!!

Version above 2 has a completely rewritten code, partially backwards compatible

Now `@Expose` and `@Exclude` decorators are used to define model fields, the new version is rigidly dependent on class-transform

Dependencies are not used original, but forks with additional necessary properties, when using this library, you need to replace all original imports with forks with modifications

Fork [class-validator-multi-lang](https://github.com/EndyKaufman/class-validator-multi-lang) - adds translation capability for errors (PR:[https://github.com/typestack/class-validator/pull/743](https://github.com/typestack/class-validator/pull/743))

Fork [class-transformer-global-storage](https://github.com/petrzjunior/class-transformer) - adds the ability to get meta information about all used classes (PR:[https://github.com/typestack/class-transformer/pull/929](https://github.com/typestack/class-transformer/pull/929))

For correct parse metadata, need remove `compilerOptions.downlevelIteration` and append `compilerOptions.emitDecoratorMetadata: true` in `tsconfig.json`

Native Angular validators not supported

## Links

[Demo](https://endykaufman.github.io/ngx-dynamic-form-builder) - Demo application with ngx-dynamic-form-builder.

[Stackblitz](https://stackblitz.com/edit/ngx-dynamic-form-builder) - Simply sample of usage on https://stackblitz.com

## Usage

company.ts

```typescript
import { Validate, IsNotEmptym } from 'class-validator-multi-lang';
import { TextLengthMore15 } from '../utils/custom-validators';
import { marker } from '@ngneat/transloco-keys-manager/marker';
import { Expose, Type } from 'class-transformer-global-storage';

export class Company {
  @Expose()
  id: number;

  @Validate(TextLengthMore15, {
    message: marker('The company name must be longer than 15'),
  })
  @IsNotEmpty()
  @Expose()
  name: string;

  constructor(data?: any) {
    if (data === undefined) {
      data = {};
    }
    this.id = data.id;
    this.name = data.name;
  }
}
```

app.module.ts

```typescript
import { FormsModule, ReactiveFormsModule } from '@angular/forms';
import { CompanyPanelComponent } from './company-panel.component';

@NgModule({
  imports: [
    ...
    FormsModule,
    ReactiveFormsModule,
    ...
  ],
  declarations: [
    ...
    CompanyPanelComponent,
    ...
  ],
  ...
})
export class AppModule {}
```

company-panel.component.html

```html
<form [formGroup]="form" *ngIf="form?.customValidateErrors | async as errors" novalidate>
  <input formControlName="name" placeholder="Name" />
  <p *ngIf="errors.name?.length">Error: {{errors.name[0]}}</p>
  <p>Form status: {{ form.status | json }}</p>
  <p>Form class-validator-multi-lang errors: {{errors|json}}</p>
  <p *ngIf="savedItem">Saved item: {{savedItem|json}}</p>
  <button (click)="onLoadClick()">Load</button>
  <button (click)="onClearClick()">Clear</button>
  <button (click)="onSaveClick()" [disabled]="!form.valid">Save</button>
</form>
```

company-panel.component.ts

```typescript
import { DynamicFormGroup, DynamicFormBuilder } from 'ngx-dynamic-form-builder';
import { Company } from './../../shared/models/company';
import { Input, Component } from '@angular/core';
import { Validators } from '@angular/forms';

@Component({
  selector: 'company-panel',
  templateUrl: './company-panel.component.html',
})
export class CompanyPanelComponent {
  form: DynamicFormGroup<Company>;

  @Input()
  item = new Company({
    id: 11,
    name: '123456789012345',
  });

  fb = new DynamicFormBuilder();

  savedItem?: Company;

  constructor() {
    this.form = this.fb.rootFormGroup(Company, {
      name: '',
    });
  }
  onLoadClick(): void {
    this.savedItem = undefined;
    this.form.object = this.item;
  }
  onClearClick(): void {
    this.savedItem = undefined;
    this.form.object = new Company();
  }
  onSaveClick(): void {
    if (this.form.valid) {
      this.savedItem = this.form.object;
    } else {
      this.savedItem = undefined;
    }
  }
}
```

custom-validators.ts

```typescript
import { ValidatorConstraintInterface, ValidatorConstraint } from 'class-validator-multi-lang';

@ValidatorConstraint()
export class TextLengthMore15 implements ValidatorConstraintInterface {
  validate(text: string) {
    return text ? text.length > 15 : false;
  }
}
```

## Support multi-language translate validation errors (I18n)

Because multi-language supported in class-validator-multi-lang, now ngx-dynamic-form-builder also support this feature

set validation messages as settings when create form group

```typescript
this.form = this.fb.rootFormGroup(
  Company,
  {
    name: '',
  },
  {
    classValidatorOptions: {
      messages: {
        'The company name must be longer than 15': 'company name must be longer than 15 (translate on other language)',
      },
    },
  }
);
```

set validation messages on runtime after for exists form group

```typescript
this.form.patchDynamicFormBuilderOptions({
  classValidatorOptions: {
    messages: {
      'The company name must be longer than 15': 'company name must be longer than 15 (translate on other language)',
    },
  },
});
```

set translate property name in error

```typescript
this.form.patchDynamicFormBuilderOptions({
  classValidatorOptions: {
    titles: {
      regionNum: 'number of region (translate property name in error on other language)',
    },
  },
});
```

set validation messages and properties name global for all instance of form group in project

```typescript
setGlobalDynamicFormBuilderOptions({
  classValidatorOptions: {
    messages: {
      'The company name must be longer than 15': 'company name must be longer than 15 (translate on other language)',
    },
    titles: {
      regionNum: 'number of region (translate property name in error on other language)',
    },
  },
});
```

## Observable Errors

The customValidateErrors property can be subscribed for cases in which your code should act on changes in errors

company-panel.component.html

```html
<form [formGroup]="form" *ngIf="form?.customValidateErrors | async as errors" novalidate>
  <input formControlName="name" placeholder="Name" />
  <p *ngIf="errors.name?.length">Error: {{errors.name[0]}}</p>
  <p>Form status: {{ form.status | json }}</p>
  <p>Observable validation errors: {{errors|json}}</p>
  <p *ngIf="savedItem">Saved item: {{savedItem|json}}</p>
  <button (click)="onLoadClick()">Load</button>
  <button (click)="onClearClick()">Clear</button>
  <button (click)="onSaveClick()" [disabled]="!form.valid">Save</button>
</form>
```

company-panel.component.ts

```typescript
import { DynamicFormGroup, DynamicFormBuilder } from 'ngx-dynamic-form-builder';
import { Company } from './../../shared/models/company';
import { Input, Component } from '@angular/core';
import { Validators } from '@angular/forms';
import { Subscription } from 'rxjs';

@Component({
  selector: 'company-panel',
  templateUrl: './company-panel.component.html',
})
export class CompanyPanelComponent implements onDestroy {
  form: DynamicFormGroup<Company>;

  @Input()
  item = new Company({
    id: 11,
    name: '123456789012345',
  });

  @Input()
  strings = Company.strings;

  fb = new DynamicFormBuilder();

  savedItem?: Company;

  errorChangeSubscription: Subscription;

  constructor() {
    this.form = this.fb.rootFormGroup(Company, {
      name: '',
    });

    this.errorChangeSubscription = this.form.customValidateErrors.subscribe((allErrors) => {
      console.log(`Errors changed: ${allErrors}`);
    });
  }
  ngOnDestroy() {
    if (this.errorChangeSubscription != null && this.errorChangeSubscription.closed === false) {
      this.errorChangeSubscription.unsubscribe();
    }
  }
  onLoadClick(): void {
    this.savedItem = undefined;
    this.form.object = this.item;
    this.form.validateAllFormFields();
  }
  onClearClick(): void {
    this.savedItem = undefined;
    this.form.object = new Company();
    this.form.validateAllFormFields();
  }
  onSaveClick(): void {
    this.form.validateAllFormFields();
    if (this.form.valid) {
      this.savedItem = this.form.object;
    } else {
      this.savedItem = undefined;
    }
  }
}
```

## License

MIT