Update Dropdown to Maintain Input Format Consistency

src/app/components/dropdown/dropdown.html

@@ -6,7 +6,7 @@
   <div #searchInput class="dropdown-input" [class.hidden]="!isOpen()" [class.focus-mode]="inputFocusMode()"
        contenteditable="true" role="textbox" aria-multiline="false" [aria-placeholder]="translation.common.selectOption"
        [attr.placeholder]="translation.common.selectOption" tabindex="-1" spellcheck="false"
-       (input)="onSearch($event)" (click)="handleInputClick($event)" (mousedown)="handleInputMouseDown()"></div>
+       (input)="onSearch($event)" (click)="handleInputClick($event)" (mousedown)="handleInputMouseDown()" (beforeinput)="preprocessInputContent($event)"></div>
 
   @if (!isOpen()) {
     <span class="placeholder">{{ selectedLabel() }}</span>

src/app/components/dropdown/dropdown.ts

@@ -13,7 +13,7 @@ import {
   viewChild,
   untracked,
 } from '@angular/core';
-import { CommonModule } from '@angular/common'
+import { CommonModule } from '@angular/common';
 import { TranslationService } from '../../services/translation.service';
 
 export interface DropdownOption {
@@ -106,7 +106,7 @@ export class Dropdown implements OnInit {
   });
 
   filteredOptions = computed(() => {
-    const query = this.searchQuery().toLowerCase().trim().normalize("NFKD");
+    const query = this.searchQuery().toLowerCase().trim().normalize('NFKD');
     const opts = this.normalizedOptions();
 
     if (!this.inputFocusMode()) return opts;
@@ -170,6 +170,8 @@ export class Dropdown implements OnInit {
       const options = this.filteredOptions();
       if (currentIndex >= 0 && currentIndex < options.length) {
         this.selectOption(options[currentIndex]);
+      } else if (options.length === 0) {
+        this.close();
       }
     } else {
       this.toggle();
@@ -218,8 +220,9 @@ export class Dropdown implements OnInit {
   }
 
   onKeyDown(event: KeyboardEvent) {
-    if (event.ctrlKey || event.metaKey || event.altKey || event.shiftKey || event.key == 'Tab')
+    const textArrowKeys = ['ArrowLeft', 'ArrowRight'];
-      return;
+
+    if (!textArrowKeys.includes(event.key)) return;
     if (!this.isOpen() || this.inputFocusMode()) return;
 
     this.inputFocusMode.set(true);
@@ -257,6 +260,9 @@ export class Dropdown implements OnInit {
   }
 
   onSearch(event: Event) {
+    if (!this.isOpen()) return;
+    if (!this.inputFocusMode()) this.inputFocusMode.set(true);
+
     const element = event.target as HTMLElement;
     const text = element.innerText;
 
@@ -265,6 +271,21 @@ export class Dropdown implements OnInit {
     this.searchQuery.set(text);
   }
 
+  preprocessInputContent(event: InputEvent) {
+    if (event.inputType === 'insertLineBreak' || event.inputType === 'insertParagraph') {
+      event.preventDefault();
+    }
+
+    if (event.inputType === 'insertFromPaste') {
+      const originalText = event.dataTransfer!.getData('text/plain');
+      const modifiedText = originalText.replace(/[\r\n]+/g, '');
+      event.preventDefault();
+
+      // noinspection JSDeprecatedSymbols
+      document.execCommand('insertText', false, modifiedText);
+    }
+  }
+
   selectedLabel = computed(() => {
     const selected = this.normalizedOptions().find((o) => o.value === this.value());
     return selected ? selected.label : this.placeholder();