FormArray And Checkbox

最近在學 Angular，他的 Form 相關模組挺有趣的，不過為了實現某些功能還是必須透過 JS 加工，這邊記錄一下怎麼綁 checkbox 的 cheked 結果到 FormBuilder 上。

html

<h3>{{ form.value | json }}</h3>  
<div [formGroup]="form">  
 <input type="text" formControlName="name">  
 <ng-container *ngFor="let hobby of hobbies">  
 <label> <input type="checkbox" [value]="hobby.value" (click)="updateHobbies($event)">  
  {{ hobby.name }}  
  </label>  
 </ng-container></div>

ts

import { Component, OnInit } from '@angular/core';
import { FormArray, FormBuilder, FormControl } from '@angular/forms';

@Component({
  selector: 'app-checkbox',
  templateUrl: './checkbox.component.html',
  styleUrls: ['./checkbox.component.scss']
})
export class CheckboxComponent implements OnInit {
  public form = this.fb.group({
    name: [''],
    hobbies: this.fb.array([])
  });
  public hobbies: object[] = [
    { name: 'basketball', value: 'basketball' },
    { name: 'baseball', value: 'baseball' },
    { name: 'tennis', value: 'tennis' },
  ];

  constructor(
    private fb: FormBuilder
  ) { }

  ngOnInit(): void {
  }

  public updateHobbies(e): void {
    const hobbies: FormArray = this.form.get('hobbies') as FormArray;

    if (e.target.checked) {
      hobbies.push(this.fb.control(e.target.value));
    } else {
      let i = 0;

      hobbies.controls.forEach((control: FormControl) => {
        if (control.value === e.target.value) {
          hobbies.removeAt(i);

          return;
        }

        ++i;
      });
    }
  }
}