我有一个formarray。如果我使用表单构建器对其进行初始化并推动它，它似乎可以正常工作。如果我采用与从中推送项目相同的数组，并尝试使用展开运算符一次将其全部添加，我会收到错误“错误错误：找不到路径的控件：'sizesArray -> 0'”

我的问题是，按照 ngrx/rsjx/功能响应式编程的精神，我怎样才能保持 Formarray '不可变'并从 FormGroup[] 分配给它，而不是清除、循环和推送？

以下是相关代码：

sizesArray: FormArray;
sizesArray2: FormArray;
sizes: Observable;

constructor(
    private productStore: Store,
    private fb: FormBuilder
  ) {
    this.sizes = productStore.select(productState.selectSizes);
  }

ngOnInit() {


    this.sizesArray = this.fb.array([]);
    this.sizesArray2 = this.fb.array([]);

    this.sizes
      .pipe(
        skipWhile(sizes => !sizes),
        map(sizes => {
         return sizes.map(size => this.fb.group({size}));
        }
       )
      )
      .subscribe(
        sizes => {
          // this is the code I want to use.  that throws the error
          this.sizesArray = this.fb.array([...sizes]);

          // this code works, but I don't know how it's different than the code above
          this.sizesArray2.clear();
          sizes.forEach( size => {
            this.sizesArray2.push(size);
          });

        }
      );

    this.sizeForm = this.fb.group({
      sizesArray: this.sizesArray
    });

  }

还有我的模板：

...

      

        
Sizes
        

            

            
            
          
        
      
      Add Size
      Back
      Save
    
...

谢谢！