<form [formGroup]="myForm">
  <p>Language</p>
    <div *ngFor="let data of languages let i = index">
        <input type="checkbox" (change)="onChange(data.name, $event.target.checked)"> {{data.name}}<br>
    </div>

<p>Age List</p>
  <button (click)="checkAll()">Check all</button>
    <button (click)="deselectAll()">Deselect all</button>
  <div *ngFor="let data of ages let j = index">
        <input type="checkbox" (change)="onAgeChange(data.name, $event.target.checked)"> {{data.name}}<br>
    </div>
</form>

<pre>Form values: {{myForm.value | json}}</pre>

ages = [{ ageID: 100 ,name: "0 -10 years" }, {ageID: 200 ,name: "10 -20 years" }, {ageID: 300 ,name: "30 -40 years" }, { ageID: 400 ,name: "40 -50 years"  }]
  languages = [{ langID: 1 ,name: "English" }, {langID: 2 ,name: "Tamil" }, {langID: 3 ,name: "Hindi" }, { langID: 4 ,name: "French"  }]


  myForm: FormGroup;

  constructor(private fb: FormBuilder) { }

  ngOnInit() {
    this.myForm = this.fb.group({
      userage: this.fb.array([]),
      userlanguage: this.fb.array([])
    });
  }

  onChange(language: string, isChecked: boolean) {
    const languageFormArray = <FormArray>this.myForm.controls.userlanguage;

    if (isChecked) {
      languageFormArray.push(new FormControl(language));
    } else {
      let index = languageFormArray .controls.findIndex(x => x.value == language)
      languageFormArray .removeAt(index);
    }
  }

  onAgeChange(age : string, isChecked: boolean) {
    const ageFormArray = <FormArray>this.myForm.controls.userage;

    if (isChecked) {
      ageFormArray.push(new FormControl(age));

    } else {
      let index = ageFormArray.controls.findIndex(x => x.value == age)
      ageFormArray.removeAt(index);
    }
  }


  checkAll(){
    const languageFormArray = <FormArray>this.myForm.controls.userlanguage;
    //console.log(this.myForm.controls['userage'])
 this.myForm.controls['userage'].setValue(
        this.myForm.controls['userage'].value
            .map(value => true)
    );
  }