Within the "additionalForm" group, there is a formArray named "validations" that dynamically binds values to the validtionsField array. The validtionsField array contains three objects with two values that need to be compared: Min-length and Max-Length.
For example, if the min length entered is greater than the max length, an error should be displayed.
Below is the code for this functionality:
import {
Component,
OnInit,
Inject
} from "@angular/core";
import {
FormControl,
FormArray,
FormGroup,
FormBuilder,
Validators,
AbstractControl,
ValidationErrors,
NgControlStatus,
ValidatorFn
} from "@angular/forms";
import {
MatDialogRef,
MAT_DIALOG_DATA,
MatSnackBar
} from "@angular/material";
@Component({
selector: "app-root",
templateUrl: "./app.component.html",
styleUrls: ["./app.component.scss"]
})
export class AppComponent implements OnInit {
validtionsField = [{
validField: "Min Length",
type: false,
fieldType: "input",
value: 1,
keyval: "minLength"
},
{
validField: "Max Length",
type: false,
fieldType: "input",
value: 50,
keyval: "maxLength"
},
{
validField: "DataType",
type: false,
fieldType: "dropDown",
dataTypeList: [],
dataTypeId: "minLength",
keyval: "dataTypeId",
value: 874
}
];
dataType = [{
id: 3701,
localeId: 1,
tenantId: 1,
parentCategoryId: null,
parentContentId: 873,
name: "Alphabets",
description: null
},
{
id: 3702,
localeId: 1,
tenantId: 1,
parentCategoryId: null,
parentContentId: 874,
name: "Alphanumeric",
description: null
}
];
additionalForm: FormGroup = this.fb.group({
fieldName: ["", [Validators.required]],
validations: this.fb.array([])
});
constructor(public fb: FormBuilder) {}
ngOnInit() {
let frmArray = this.additionalForm.get("validations") as FormArray;
for (let data of this.validtionsField) {
frmArray.push(this.initSection(data));
}
}
initSection(data) {
return this.fb.group({
validField: [data.validField, [Validators.required]],
type: [data.type, [Validators.required]],
value: [data.value, [Validators.required]],
dataTypeList: [this.dataType, [Validators.required]],
fieldType: [data.fieldType, [Validators.required]],
validArray: []
}, {
validator: this.customValidator
});
}
checkFieldType(data): any {
return data === "dropDown";
}
// Function to compare values of min and max length
public customValidator(control: AbstractControl): ValidationErrors | null {
const newValue = control.get("value") ? control.get("value").value : null;
const values = control.get("value") ? control.get("value").value : [];
console.log("1 " + newValue);
console.log(values);
for (let i = 0, j = values.length; i < j; i++) {
if (newValue === values[i]) {
return {
duplicate2: true
};
}
}
return null;
}
}<form [formGroup]="additionalForm">
<mat-form-field>
<input formControlName='fieldName' placeholder="Field Name" required matInput>
</mat-form-field>
<div class="row">
<div class="col-md-12 col-sm-12">
\
<div formArrayName="validations">
<ng-container *ngFor="let validationForm of additionalForm.controls.validations.controls; let i = index">
<div class="valid-data" [formGroupName]="i">
<span>
<label>{{validationForm.value.validField }}</label>
</span>
<span>
<ng-container *ngIf="checkFieldType(validationForm.value.fieldType ); else input">
<mat-form-field class="select-dataType">
<mat-select required formControlName='value' placeholder="Datatype">
<mat-option *ngFor="let fieldTypeData of validationForm.value.dataTypeList"
[value]='fieldTypeData.parentContentId'>
{{fieldTypeData.name}}</mat-option>
</mat-select>
</mat-form-field>
</ng-container>
<ng-template #input>
<mat-form-field>
<input required formControlName='value' pattern= "[0-9]+" matInput>
</mat-form-field>
</ng-template>
</span>
<div *ngIf="validationForm.get('value')?.touched ">
<div class="error" *ngIf="validationForm.get('value').hasError('required')">
{{validationForm.value.validField}} is required
</div>
</div>
</div>
</ng-container>
</div>
</div>
</div>
</form>The TS and HTML code above corresponds to the function below, where I am attempting to compare old and new values from the control, but it is returning values from the same input field for the same min-length:
/// Trying the function below to compare the min and max length.
public customValidator(control: AbstractControl): ValidationErrors | null {
const newValue = control.get('value') ? control.get('value').value : null;
const values = control.get('value') ? control.get('value').value : [];
console.log("1 " + newValue);
console.log(values);
for (let i = 0, j = values.length; i < j; i++) {
if (newValue === values[i]) {
return {
'duplicate2': true
};
}
}
return null;
}I require assistance in comparing values from a dynamic form array, where all values entered into the form-array object are bound to the formControlName "value".
Click on the following link for the code :
https://stackblitz.com/edit/angular6-material-components-demo-wgtafn