Override the custom validator angular 2

I am new in angular 2 and I want to implement a custom validator for form control that takes a boolean ( requiredAttribute) as parameter.

if this parameter is true so the form control is required else it is not required.

I have implemented this but seems don't works. All inputs (Form contol) becoms required. I have implemented this function that represent the custom validator.

 function inputRequired( requiredAttribute: boolean) {
  return (control: FormControl): { [s: string]: boolean } => {
    if (requiredAttribute === false) {
      return {'input is not required': true};
    }else {
      return null;
    }
  };
}

And I have placed it in the initForm method. Then for the input form text for my reactive form:

 text: new FormControl('', [Validators.compose([inputRequired(this.selectedOperation.inputs[i].required)])]),

The final code

private initForm() {
function inputRequired( requiredAttribute: boolean) {
  return (control: FormControl): { [s: string]: boolean } => {
    if (requiredAttribute === false) {
      return {'input is not required': true};
    }else {
      return null;
    }
  };
}
let operationName: any;
const operationInputs: FormArray = new FormArray([]);

if (this.selectedOperation.inputs != null) {
  for (let i = 0; i < this.selectedOperation.inputs.length; i++ ) {
    operationInputs.push(
      new FormGroup({
        name: new FormControl(this.selectedOperation.inputs[i].name),
        text: new FormControl('', [Validators.compose([inputRequired(this.selectedOperation.inputs[i].required)])]),
    defaultText: new FormControl(this.selectedOperation.inputs[i].defaultText),
      complexType: new FormControl(this.selectedOperation.inputs[i].complexType),
      type: new FormControl(this.selectedOperation.inputs[i].type),
      isMultivalued: new FormControl(this.selectedOperation.inputs[i].isMultiValued),
      values: new FormControl(this.selectedOperation.inputs[i].values),
      indicator: new FormControl(this.selectedOperation.inputs[i].indicator),
      required: new FormControl(this.selectedOperation.inputs[i].required),
      isSelected: new FormControl(this.selectedOperation.inputs[i].isSelected),
      simpleTypeVarietyOrComplexTypeContent: new FormControl(this.selectedOperation.inputs[i].simpleTypeVarietyOrComplexTypeContent),
      choiceContent: new FormControl(this.selectedOperation.inputs[i].choiceContent),
      inputQname: new FormControl(this.selectedOperation.inputs[i].inputQname),
        attributes: new FormControl(this.selectedOperation.inputs[i].attributes),
      children: operationInputsChildren,

      })
    );
  }
}
operationName = this.selectedOperation.name;
this.operationRequestForm = this.formBuilder.group({
    wsdlPath: [this.wsdlPath],
    name: [operationName],
    inputs: operationInputs,
  operationDateInvoke: ['', Validators.required],
  operationTimeInvoke: ['', Validators.required]
});

}

and the input is an object of CustomInput class that has required as attribute.

  export class CustomInput {

              constructor(public name: string, public text: string, public 
               defaultText: string,
          public complexType: boolean, public type: string, public children: 
            CustomInput[] = [],
          public isMultiValued: boolean,
          public values: string[] = [], public indicator: string, public 
           required: boolean,
          public isSelected: boolean, public 
            simpleTypeVarietyOrComplexTypeContent: number,
          public choiceContent: boolean, public inputQname: string,
          public attributes: Map<string, string> = new Map<string, string>() 
    ) {}
   }

An operation has many inputs elements. I want to create a reactive form for the operation. If the input element is required( its attribute required eqaul to true) then the HTML input associated to the operation input element is required.

So how I implement a custom validator that takes a boolean parameter and if this parameter is true then the form control is required else is not.

Thanks