From ff5c4e5d881695f637820dd101709cfc7c7bbb65 Mon Sep 17 00:00:00 2001
From: Thomas Heller <thomas.heller@dynatrace.com>
Date: Wed, 8 Jul 2020 13:36:18 +0200
Subject: [PATCH] fix(filter-field): Fixes an issue with validation flickering
 on free text.

Fixes #1180
---
 .../filter-field/src/filter-field-validation.ts             | 2 +-
 libs/barista-components/filter-field/src/filter-field.ts    | 6 +++++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/libs/barista-components/filter-field/src/filter-field-validation.ts b/libs/barista-components/filter-field/src/filter-field-validation.ts
index bee1f0d098..781b3e32af 100644
--- a/libs/barista-components/filter-field/src/filter-field-validation.ts
+++ b/libs/barista-components/filter-field/src/filter-field-validation.ts
@@ -28,7 +28,7 @@ export interface DtFilterFieldValidator {
 export class DtFilterFieldControl extends FormControl {
   constructor(private _validators: DtFilterFieldValidator[] = []) {
     super(
-      null,
+      '',
       _validators.map((validator) => validator.validatorFn),
       null,
     );
diff --git a/libs/barista-components/filter-field/src/filter-field.ts b/libs/barista-components/filter-field/src/filter-field.ts
index 605e1c5931..733cd4e6e0 100644
--- a/libs/barista-components/filter-field/src/filter-field.ts
+++ b/libs/barista-components/filter-field/src/filter-field.ts
@@ -945,7 +945,11 @@ export class DtFilterField<T = any>
 
   /** Write a value to the filter field control if there is a control active */
   private _writeControlValue(value: string): void {
-    if (this._control) {
+    // Only write the value when it is actually different
+    // setting the value to it's old value and marking the control
+    // dirty will trigger validation too many times, resulting in a flickering
+    // of the validation flag.
+    if (this._control && this._control.value !== value) {
       this._control.setValue(value);
       this._control.markAsDirty();
       this._control.markAsTouched();