there are floor area and rented area in the form
how to verify that the rented area must be less than or equal to the floor area

Xiaobai asks for advice

  add = this.form.group({
    buildingId: [null, [Validators.required]],
    roomNo: [null, [Validators.required]],
    roomResourceType: ["1"],
    roomBuildAcreage: [null, [Validators.required]],
    roomEquipments: [null],
    roomDecorateState: ["1"],
    roomRentedAcreage: [null, [Validators.required, this.validateRentedAcreage,rentedAcreageValidator(add)]],
    roomResourceState: ["1", [Validators.required]],
    isCharge: ["1", [Validators.required]],
    heatingCost: [null, [Validators.required]],
    roomDesc: [null],
  });