Joi: "tel" is not allowed to be empty

Question

Joi is returning the following error even though tel is set to be optional. How do we fix this?

Thanks.

Error: Joi Failed: ValidationError: child "tel" fails because ["tel" is not allowed to be empty]

---

//Define Joi schema
const schema = {
    email: Joi.string().required().email({
        errorLevel: 64,
        minDomainAtoms: 2 
    }).min(6),
    tel: Joi.string().optional().min(10).max(10),
    password: Joi.string().required().min(8).max(64)
}

//Check inputs
const { error, value } = Joi.validate({ 
    email: args.email, 
    tel: tel, 
    password: args.password 
}, schema)   

Answer 1

...empty strings are not allowed by default and must be enabled with allow(''). However, if you want to specify a default value in case of empty string you have to use a different pattern: Joi.string().empty('').default('default value'). This tells Joi that the empty string should be considered as an empty value (instead of invalid) and which value to use as default.

Reference: Joi v10.6.0 Documetations

In your case:

tel: Joi.string().optional().allow('').min(10).max(10)