feat(*): adding external validator logic for input

Author: ChronosSF

projects/igniteui-angular/src/lib/combo/combo.common.ts

@@ -1300,6 +1300,10 @@ export abstract class IgxComboBaseDirective implements IgxComboBase, AfterViewCh
         this.manageRequiredAsterisk();
     };
 
+    protected externalValidate(): IgxInputState {
+        return this._valid;
+    }
+
     private updateValidity() {
         if (this.ngControl && this.ngControl.invalid) {
             this.valid = IgxInputState.INVALID;

projects/igniteui-angular/src/lib/combo/combo.component.html

@@ -9,7 +9,7 @@
         <ng-content select="igx-hint, [igxHint]"></ng-content>
     </ng-container>
     <input igxInput #comboInput name="comboInput" type="text" [value]="displayValue" readonly
-        [attr.required]="required"
+        [externalValidate]="externalValidate"
         [attr.placeholder]="placeholder" [disabled]="disabled"
         role="combobox" aria-haspopup="listbox"
         [attr.aria-expanded]="!dropdown.collapsed" [attr.aria-controls]="dropdown.listId"

projects/igniteui-angular/src/lib/directives/input/input.directive.ts

@@ -102,6 +102,7 @@ export class IgxInputDirective implements AfterViewInit, OnDestroy {
     private _valueChanges$: Subscription;
     private _fileNames: string;
     private _disabled = false;
+    private _externalValidate: () => IgxInputState = null;
 
     constructor(
         public inputGroup: IgxInputGroupBase,
@@ -195,6 +196,20 @@ export class IgxInputDirective implements AfterViewInit, OnDestroy {
         this.nativeElement.required = this.inputGroup.isRequired = value;
     }
 
+    /**
+     * @hidden @internal
+     * Sets a function to validate the input externally.
+     * This function should return an `IgxInputState` value.
+    */
+    @Input()
+    public set externalValidate(fn: () => IgxInputState) {
+        this._externalValidate = fn;
+    }
+
+    public get externalValidate(): () => IgxInputState {
+        return this._externalValidate;
+    }
+
     /**
      * Gets whether the igxInput is required.
      *
@@ -367,7 +382,9 @@ export class IgxInputDirective implements AfterViewInit, OnDestroy {
      * @internal
      */
     protected updateValidityState() {
-        if (this.ngControl) {
+        if (this._externalValidate) {
+            this._valid = this._externalValidate();
+        } else if (this.ngControl) {
             if (!this.disabled && this.isTouchedOrDirty) {
                 if (this.hasValidators) {
                     // Run the validation with empty object to check if required is enabled.