Add Dropdown Search Feature

src/app/components/dropdown/dropdown.html

@@ -2,13 +2,21 @@
   @if (icon()) {
     <span class="material-symbols-outlined icon-24 prefix-icon">{{ icon() }}</span>
   }
+
+  <div #searchInput class="dropdown-input" [class.hidden]="!isOpen()"
+       contenteditable="true" role="textbox" aria-multiline="false" [aria-placeholder]="translation.common.selectOption" tabindex="-1" spellcheck="false"
+       (input)="onSearch($event)"></div>
+
+  @if (!isOpen()) {
     <span class="placeholder">{{ selectedLabel() }}</span>
+  }
   <span class="material-symbols-outlined icon-24 chevron" [class.open]="isOpen()">keyboard_arrow_down</span>
 </div>
 
 @if (isOpen()) {
+  <div class="dropdown-container">
     <ul class="dropdown-list" role="listbox" [id]="dropdownId + '-listbox'">
-    @for (option of normalizedOptions(); track option.value; let i = $index) {
+      @for (option of filteredOptions(); track option.value; let i = $index) {
         <li
           class="dropdown-item"
           role="option"
@@ -21,4 +29,5 @@
         </li>
       }
     </ul>
+  </div>
 }

src/app/components/dropdown/dropdown.scss

@@ -38,6 +38,11 @@ $default_animation_duration: 0.2s;
   cursor: pointer;
 
   max-width: 100%;
+
+  &:focus-within {
+    outline: 2px solid list.nth(library.$brand_palette, 5);
+    outline-offset: 2px;
+  }
 }
 
 .dropdown-box {
@@ -55,12 +60,28 @@ $default_animation_duration: 0.2s;
   }
 
   .placeholder {
+    text-overflow: ellipsis;
+  }
+
+  .dropdown-input:focus-visible {
+    outline: none;
+  }
+
+  .dropdown-input.hidden {
+    position: absolute;
+
+    width: 0;
+    height: 0;
+    opacity: 0;
+    visibility: hidden;
+  }
+
+  .placeholder, .dropdown-input {
     flex-grow: 1;
     font-size: 18px;
     height: 24px;
     white-space: nowrap;
     overflow: hidden;
-    text-overflow: ellipsis;
     user-select: none;
 
     align-content: center;
@@ -78,22 +99,48 @@ $default_animation_duration: 0.2s;
   }
 }
 
-.dropdown-list {
+.dropdown-container {
   position: absolute;
   top: calc(100% + 4px);
   left: 0;
   width: 100%;
   padding: 0;
   margin: 0;
-  list-style: none;
   background-color: light-dark(oklch(1 0 0), oklch(0 0 0));
   border-radius: $border_radius;
   z-index: 1000;
   max-height: 240px;
-  overflow-y: auto;
+  overflow-y: hidden;
   box-shadow: 0 4px 12px oklch(0 0 0 / 10%); // rgba(0, 0, 0, 0.1)
   animation: slideIn var(--animation-duration) $animation_timing;
 
+  .dropdown-list {
+    padding: 0;
+    margin: 0;
+    list-style: none;
+    width: 100%;
+    max-height: inherit;
+    overflow-y: auto;
+
+    scrollbar-color: light-dark(oklch(0 0 0 / 10%), oklch(1 0 0 / 20%)) transparent;
+
+    &::-webkit-scrollbar {
+      width: 12px;
+    }
+
+    &::-webkit-scrollbar-track {
+      background: transparent;
+    }
+
+    &::-webkit-scrollbar-thumb {
+      border: 2px solid transparent;
+      background-clip: padding-box;
+
+      background-color: light-dark(oklch(0 0 0 / 10%), oklch(1 0 0 / 20%));
+      border-radius: 10px;
+    }
+  }
+
   &::after {
     content: "";
     position: absolute;

src/app/components/dropdown/dropdown.ts

@@ -1,6 +1,20 @@
-import { Component, input, model, output, signal, HostListener, ElementRef, computed, OnInit
-} from '@angular/core'
+import {
+  Component,
+  input,
+  model,
+  output,
+  signal,
+  HostListener,
+  ElementRef,
+  computed,
+  OnInit,
+  inject,
+  effect,
+  viewChild,
+  untracked,
+} from '@angular/core';
 import { CommonModule } from '@angular/common'
+import { TranslationService } from '../../services/translation.service';
 
 export interface DropdownOption {
   label: string;
@@ -24,6 +38,7 @@ export interface DropdownOption {
     '[class.open]': 'isOpen()',
     tabindex: '0',
     '(click)': 'toggle()',
+    '(keydown)': 'onKeyDown($event)',
     '(keydown.enter)': 'onEnter($event)',
     '(keydown.space)': 'onSpaceDown($event)',
     '(keydown.escape)': 'close()',
@@ -32,6 +47,9 @@ export interface DropdownOption {
   },
 })
 export class Dropdown implements OnInit {
+  translation = inject(TranslationService).translation;
+  searchInput = viewChild<ElementRef<HTMLElement>>('searchInput');
+
   options = input<Array<DropdownOption | string>>([]);
   placeholder = input<string>('Select an option');
   ariaLabel = input<string | undefined>(undefined);
@@ -41,12 +59,28 @@ export class Dropdown implements OnInit {
   selectionChange = output<any>();
 
   isOpen = signal(false);
+  inputFocusMode = signal(false);
   focusedIndex = signal(-1);
+  searchQuery = signal('');
 
   private static nextId = 0;
   dropdownId = `dropdown-${Dropdown.nextId++}`;
 
-  constructor(private el: ElementRef) {}
+  constructor(private element: ElementRef) {
+    effect(() => this.filteredOptions())
+
+    effect(() => {
+      const isDropdownOpen = this.isOpen();
+
+      if (!isDropdownOpen) {
+        if (untracked(this.inputFocusMode)) this.inputFocusMode.set(false);
+        this.searchQuery.set('');
+
+        let currentValue = untracked(this.normalizedOptions).find((o) => o.value === this.value());
+        if (currentValue) this.searchInput()!.nativeElement.innerText = currentValue.label;
+      }
+    });
+  }
 
   ngOnInit() {
     const opts = this.normalizedOptions();
@@ -67,10 +101,28 @@ export class Dropdown implements OnInit {
     });
   });
 
+  filteredOptions = computed(() => {
+    const query = this.searchQuery().toLowerCase().trim();
+    const opts = this.normalizedOptions();
+
+    if (!this.inputFocusMode()) return opts;
+    if (!query) return opts;
+
+    return opts.filter((o) => o.label.toLowerCase().includes(query));
+  });
+
   toggle() {
     this.isOpen.update((v) => !v);
     if (this.isOpen()) {
+      this.searchQuery.set('');
       this.focusedIndex.set(this.normalizedOptions().findIndex((o) => o.value === this.value()));
+
+      requestAnimationFrame(() => {
+        const searchInputElement = this.searchInput()!.nativeElement;
+
+        searchInputElement.focus();
+        this.setCursorToEnd(searchInputElement);
+      })
     }
   }
 
@@ -85,28 +137,25 @@ export class Dropdown implements OnInit {
     this.close();
   }
 
-  onEnter(event: Event) {
-    event.preventDefault();
+  onConfirm(event: Event) {
+    event.preventDefault()
+
     if (this.isOpen()) {
       const currentIndex = this.focusedIndex();
-      if (currentIndex >= 0 && currentIndex < this.normalizedOptions().length) {
-        this.selectOption(this.normalizedOptions()[currentIndex]);
+      const options = this.filteredOptions();
+      if (currentIndex >= 0 && currentIndex < options.length) {
+        this.selectOption(options[currentIndex]);
       }
     } else {
       this.toggle();
     }
   }
 
+  onEnter(event: Event) { this.onConfirm(event) }
+
   onSpaceDown(event: Event) {
-    event.preventDefault();
-    if (this.isOpen()) {
-      const currentIndex = this.focusedIndex();
-      if (currentIndex >= 0 && currentIndex < this.normalizedOptions().length) {
-        this.selectOption(this.normalizedOptions()[currentIndex]);
-      }
-    } else {
-      this.toggle();
-    }
+    if (this.isOpen() && this.inputFocusMode()) return;
+    this.onConfirm(event)
   }
 
   onArrowDown(event: Event) {
@@ -115,9 +164,13 @@ export class Dropdown implements OnInit {
       this.toggle();
       return;
     }
+
     this.focusedIndex.update((i) => {
+      const options = this.filteredOptions();
+      if (options.length === 0) return -1;
+
       if (i === -1) return 0;
-      return (i + 1) % this.normalizedOptions().length;
+      return (i + 1) % options.length;
     });
   }
 
@@ -127,21 +180,48 @@ export class Dropdown implements OnInit {
       this.toggle();
       return;
     }
+
     this.focusedIndex.update((i) => {
-      if (i <= 0) return this.normalizedOptions().length - 1;
+      const options = this.filteredOptions();
+      if (options.length === 0) return -1;
+
+      if (i <= 0) return options.length - 1;
       return i - 1;
     });
   }
 
+  onKeyDown(event: KeyboardEvent) {
+    if (event.ctrlKey || event.metaKey || event.altKey || event.shiftKey || event.key == 'Tab') return;
+    if (!this.isOpen() || this.inputFocusMode()) return;
+
+    this.inputFocusMode.set(true);
+  }
+
   @HostListener('document:click', ['$event'])
   onDocumentClick(event: MouseEvent) {
-    if (!this.el.nativeElement.contains(event.target)) {
+    if (!this.element.nativeElement.contains(event.target)) {
       this.close();
     }
   }
 
+  onSearch(event: Event) {
+    const text = (event.target as HTMLElement).innerText;
+
+    this.focusedIndex.set(0);
+    this.searchQuery.set(text);
+  }
+
   selectedLabel = computed(() => {
     const selected = this.normalizedOptions().find((o) => o.value === this.value());
     return selected ? selected.label : this.placeholder();
   });
+
+  private setCursorToEnd(element: HTMLElement) {
+    const range = document.createRange();
+    const sel = window.getSelection();
+    range.selectNodeContents(element);
+    range.collapse(false);
+    sel?.removeAllRanges();
+    sel?.addRange(range);
+  }
 }

src/app/i18n/en.ts

@@ -18,6 +18,7 @@ export const EN = {
     signup: 'Signup',
   },
   common: {
+    selectOption: 'Select Option...',
     close: 'Close',
     save: 'Save',
   },

src/app/i18n/jp.ts

@@ -20,6 +20,7 @@ export const JP: Translation = {
     signup: '新規登録',
   },
   common: {
+    selectOption: '選択...',
     close: '閉じる',
     save: '保存',
   },

src/app/i18n/kr.ts

@@ -20,6 +20,7 @@ export const KR: Translation = {
     signup: '회원가입',
   },
   common: {
+    selectOption: '선택...',
     close: '닫기',
     save: '저장',
   },

src/app/pages/main/main.ts

@@ -17,6 +17,9 @@ export class MainPage {
     { label: 'English', value: 'EN' },
     { label: '한국어', value: 'KR' },
     { label: '日本語', value: 'JP' },
+    { label: 'Deutsch', value: 'DE' },
+    { label: 'Italiano', value: 'IT' },
+    { label: '中文', value: 'CN' },
   ];
 
   selectedDropdownValue = signal<any>(null);