autocomplete-demo.ts

/**
 * @license
 * Copyright Google LLC All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */

import {Component, ViewChild} from '@angular/core';
import {CommonModule} from '@angular/common';
import {FormControl, FormsModule, NgModel, ReactiveFormsModule} from '@angular/forms';
import {MatAutocompleteModule} from '@angular/material/autocomplete';
import {MatButtonModule} from '@angular/material/button';
import {MatLegacyCardModule} from '@angular/material/legacy-card';
import {MatFormFieldModule} from '@angular/material/form-field';
import {MatInputModule} from '@angular/material/input';
import {Observable} from 'rxjs';
import {map, startWith} from 'rxjs/operators';

export interface State {
  code: string;
  name: string;
}

export interface StateGroup {
  letter: string;
  states: State[];
}

@Component({
  selector: 'autocomplete-demo',
  templateUrl: 'autocomplete-demo.html',
  styleUrls: ['autocomplete-demo.css'],
  standalone: true,
  imports: [
    CommonModule,
    FormsModule,
    MatAutocompleteModule,
    MatButtonModule,
    MatLegacyCardModule,
    MatFormFieldModule,
    MatInputModule,
    ReactiveFormsModule,
  ],
})
export class AutocompleteDemo {
  stateCtrl = new FormControl({code: 'CA', name: 'California'});
  currentState = '';
  currentGroupedState = '';
  topHeightCtrl = new FormControl(0);

  reactiveStates: Observable<State[]>;
  tdStates: State[];

  tdDisabled = false;

  @ViewChild(NgModel) modelDir: NgModel;

  groupedStates: StateGroup[];
  filteredGroupedStates: StateGroup[];
  states: State[] = [
    {code: 'AL', name: 'Alabama'},
    {code: 'AK', name: 'Alaska'},
    {code: 'AZ', name: 'Arizona'},
    {code: 'AR', name: 'Arkansas'},
    {code: 'CA', name: 'California'},
    {code: 'CO', name: 'Colorado'},
    {code: 'CT', name: 'Connecticut'},
    {code: 'DE', name: 'Delaware'},
    {code: 'FL', name: 'Florida'},
    {code: 'GA', name: 'Georgia'},
    {code: 'HI', name: 'Hawaii'},
    {code: 'ID', name: 'Idaho'},
    {code: 'IL', name: 'Illinois'},
    {code: 'IN', name: 'Indiana'},
    {code: 'IA', name: 'Iowa'},
    {code: 'KS', name: 'Kansas'},
    {code: 'KY', name: 'Kentucky'},
    {code: 'LA', name: 'Louisiana'},
    {code: 'ME', name: 'Maine'},
    {code: 'MD', name: 'Maryland'},
    {code: 'MA', name: 'Massachusetts'},
    {code: 'MI', name: 'Michigan'},
    {code: 'MN', name: 'Minnesota'},
    {code: 'MS', name: 'Mississippi'},
    {code: 'MO', name: 'Missouri'},
    {code: 'MT', name: 'Montana'},
    {code: 'NE', name: 'Nebraska'},
    {code: 'NV', name: 'Nevada'},
    {code: 'NH', name: 'New Hampshire'},
    {code: 'NJ', name: 'New Jersey'},
    {code: 'NM', name: 'New Mexico'},
    {code: 'NY', name: 'New York'},
    {code: 'NC', name: 'North Carolina'},
    {code: 'ND', name: 'North Dakota'},
    {code: 'OH', name: 'Ohio'},
    {code: 'OK', name: 'Oklahoma'},
    {code: 'OR', name: 'Oregon'},
    {code: 'PA', name: 'Pennsylvania'},
    {code: 'RI', name: 'Rhode Island'},
    {code: 'SC', name: 'South Carolina'},
    {code: 'SD', name: 'South Dakota'},
    {code: 'TN', name: 'Tennessee'},
    {code: 'TX', name: 'Texas'},
    {code: 'UT', name: 'Utah'},
    {code: 'VT', name: 'Vermont'},
    {code: 'VA', name: 'Virginia'},
    {code: 'WA', name: 'Washington'},
    {code: 'WV', name: 'West Virginia'},
    {code: 'WI', name: 'Wisconsin'},
    {code: 'WY', name: 'Wyoming'},
  ];

  constructor() {
    this.tdStates = this.states;
    this.reactiveStates = this.stateCtrl.valueChanges.pipe(
      startWith(this.stateCtrl.value),
      map(val => this.displayFn(val)),
      map(name => this.filterStates(name)),
    );

    this.filteredGroupedStates = this.groupedStates = this.states.reduce<StateGroup[]>(
      (groups, state) => {
        let group = groups.find(g => g.letter === state.name[0]);

        if (!group) {
          group = {letter: state.name[0], states: []};
          groups.push(group);
        }

        group.states.push({code: state.code, name: state.name});

        return groups;
      },
      [],
    );
  }

  displayFn(value: any): string {
    return value && typeof value === 'object' ? value.name : value;
  }

  filterStates(val: string) {
    return val ? this._filter(this.states, val) : this.states;
  }

  filterStateGroups(val: string) {
    if (val) {
      return this.groupedStates
        .map(group => ({letter: group.letter, states: this._filter(group.states, val)}))
        .filter(group => group.states.length > 0);
    }

    return this.groupedStates;
  }

  private _filter(states: State[], val: string) {
    const filterValue = val.toLowerCase();
    return states.filter(state => state.name.toLowerCase().startsWith(filterValue));
  }
}