How to use the @rxweb/reactive-form-validators.RxwebValidators.contains function in @rxweb/reactive-form-validators

() => {
          let formBuilder = new FormBuilder();
          let formGroup = formBuilder.group({
'emailAddress':['abc@gmail.com'],
            'businessEmailAddress':'xyz@gmail.com'
          });
          expect(RxwebValidators.contains({value:'@gmail.com',conditionalExpression:(x,y) => x.emailAddress == "abc@gmail.com"})(formGroup.controls.businessEmailAddress)).toBeNull()
        });

ngOnInit() {
        this.userFormGroup = this.formBuilder.group({
            emailAddress:['', RxwebValidators.contains({value:'@gmail.com' })], 
        });
    }
}

ngOnInit() {
        this.userFormGroup = this.formBuilder.group({
            emailAddress:['', RxwebValidators.contains({value:'@gmail.com' })], 
        });
    }
}

ngOnInit() {
        this.userFormGroup = this.formBuilder.group({
            emailAddress:['', RxwebValidators.contains({value:'@gmail.com' })], 
            recoveryEmailAddress:['', RxwebValidators.contains({value:'@gmail.com'  ,conditionalExpression:'x => x.emailAddress == "abc@gmail.com"' })], 
            businessEmailAddress:['', RxwebValidators.contains({value:'@gmail.com'  ,conditionalExpression:(x,y) => x.emailAddress == "abc@gmail.com" })], 
        });
    }
}

ngOnInit() {
        this.userFormGroup = this.formBuilder.group({
            emailAddress:['', RxwebValidators.contains({value:'@gmail.com' })], 
            businessEmailAddress:['', RxwebValidators.contains({value:'@gmail.com'  ,conditionalExpression:(x,y) => x.emailAddress == "abc@gmail.com" })], 
            recoveryEmailAddress:['', RxwebValidators.contains({value:'@gmail.com'  ,conditionalExpression:'x => x.emailAddress == "abc@gmail.com"' })], 
            otherEmailAddress:['', RxwebValidators.contains({value:'@gmail.com'  ,message:'Please enter valid gmailId' })], 
        });
    }
}

ngOnInit() {
        this.userFormGroup = this.formBuilder.group({
            emailAddress:['', RxwebValidators.contains({value:'@gmail.com' })], 
            businessEmailAddress:['', RxwebValidators.contains({value:'@gmail.com'  ,conditionalExpression:(x,y) => x.emailAddress == "abc@gmail.com" })], 
            recoveryEmailAddress:['', RxwebValidators.contains({value:'@gmail.com'  ,conditionalExpression:'x => x.emailAddress == "abc@gmail.com"' })], 
            otherEmailAddress:['', RxwebValidators.contains({value:'@gmail.com'  ,message:'Please enter valid gmailId' })], 
        });
    }
}

ngOnInit() {
        this.userFormGroup = this.formBuilder.group({
            emailAddress:['', RxwebValidators.contains({value:'@gmail.com' })], 
        });
    }
}

ngOnInit() {
        this.userFormGroup = this.formBuilder.group({
            emailAddress:['', RxwebValidators.contains({value:'@gmail.com' })], 
            recoveryEmailAddress:['', RxwebValidators.contains({value:'@gmail.com'  ,conditionalExpression:'x => x.emailAddress == "abc@gmail.com"' })], 
            businessEmailAddress:['', RxwebValidators.contains({value:'@gmail.com'  ,conditionalExpression:(x,y) => x.emailAddress == "abc@gmail.com" })], 
        });
    }
}

ngOnInit() {
        this.userFormGroup = this.formBuilder.group({
            otherEmailAddress:['', RxwebValidators.contains({value:'@gmail.com'  ,message:'Please enter valid gmailId' })], 
        });
    }
}

ngOnInit() {
        this.userFormGroup = this.formBuilder.group({
            otherEmailAddress:['', RxwebValidators.contains({value:'@gmail.com'  ,message:'Please enter valid gmailId' })], 
        });
    }
}