angular5中formArray動態賦值

    this.editModel = fb.group({
      level0: this.fb.array([
        new FormGroup({
          x: new FormControl(null),
          y: new FormControl(null)
        })
      ]),
});        


for (let i = 0; i < level0.length; i++) {
          (this.editModel.controls['level0'] as FormArray).push(new FormGroup({x: new                 FormControl(level0[i][0]), y: new FormControl(level0[i][1])}));
        }