Method setControl

packages/forms/src/model/form_array.ts:258–274

* Replace an existing control. * * @param index Index in the array to replace the control. If `index` is negative, wraps around * from the back. If `index` is greatly negative (less than `-length`), replaces the first * element. This behavior is the same as `Array.splice(index, 1

(index: number, control: TControl, options: {emitEvent?: boolean} = {})

   * replaced with a new one. When false, no events are emitted.
   */
  setControl(index: number, control: TControl, options: {emitEvent?: boolean} = {}): void {
    // Adjust the index, then clamp it at no less than 0 to prevent undesired underflows.
    let adjustedIndex = this._adjustIndex(index);
    if (adjustedIndex < 0) adjustedIndex = 0;

    if (this.controls[adjustedIndex])
      this.controls[adjustedIndex]._registerOnCollectionChange(() => {});
    this.controls.splice(adjustedIndex, 1);

    if (control) {
      this.controls.splice(adjustedIndex, 0, control);
      this._registerControl(control);
    }

    this.updateValueAndValidity({emitEvent: options.emitEvent});
    this._onCollectionChange();
  }

  /**
   * Length of the control array.