Develop Reference

How to validate with .when statement in yup with parent object

I have this yup which is works:
const exceptionSchema = yup.object().shape({
exceptionRule: yup.object().shape({
exceptionCondition: yup.object().shape({
exceptionCount: yup.string().required('Exception_Count_Required')
}),
selectedExceptions: yup
.array()
.ensure()
.min(1, 'Validate_ExceptionsAssigned')
})
});
But I have to validate this subobject selectedExceptions when some other property is equals to 1:
and this doesnt work:
const exceptionSchema = yup.object().shape({
exceptionRule: yup.object().shape({
exceptionCondition: yup.object().shape({
exceptionCount: yup.string().required('Exception_Count_Required')
}),
selectedExceptions: yup
.array()
.ensure()
// .min(1, 'Validate_ExceptionsAssigned')
.when('type', {
is: 1,
then: yup
.array()
.ensure()
.min(1, 'Validate_ExceptionsAssigned')
})
})
});
this is mine model, and I think because the type proeprty is not within this object exceptionRule then yup validation does not take into consideration this .when() clause.
Model:
const newRule = () => ({
type: '',
exceptionRule: {
exceptionCondition: {
exceptionCount: '1',
condition: 1,
frequency: 1
},
selectedExceptions: [],
}
});
How to get this type from above, outside my inner object?
How can I debug this when('type') to be sure what value does it have?

How to add custom string value in validation schema using Yup

I have this basic yup validation schema for my react project.
const DisplayingErrorMessagesSchema = Yup.object().shape({
username: Yup.string()
.min(2, "Too Short!")
.max(50, "Too Long!")
.required("Required"),
email: Yup.string().email("Invalid email").required("Required")
});
For username, it currently validates the required property when the username field is an empty string, but to validate even more with multiple default strings like "none", and "admin". How can I validate these default strings also for the username field?

They have matches() method that does what you are asking:
username: Yup.string()
.matches(/(none|default)/, { message: "Username invalid", excludeEmptyString: true })
.required("Required"),

yup conditional validation of array

I want to validate the array on the base of loan register if loan register is true then array should validate else not.
yup.object().shape({
loan_register: yup.boolean(),
loans: yup.array()
.of(
yup.object().shape({
bank_name: yup.string().required(),
bank_reg_no: yup.string().required(),
loan_amount: yup.string().required(),
})
)
})

The reason why of is not an exported member from yup is because yup needs to know the type of data first. You can only use of once you know the type.
For example: array().of(), string().oneOf(), e.t.c
Hence, in your case, you need to provide the data type and it will solve your problem.
const validationSchema = yup.object({
loan_register: yup.boolean(),
loans: yup.array().when('loan_register', {
is: true,
then: yup.array().of(
yup.object({
bank_name: yup.string().required(),
bank_reg_no:yup.string().required(),
loan_amount:yup.string().required(),
}))
})
})

EDIT: 'When loan_register === true, bank_name, bank_reg_no and loan_amount must be strings and required fields.'
You can translate that requirement into code like following (include Yup conditional validation using .when() ):
const validationSchema = yup.object().shape({
loan_register: yup.boolean(),
loans: yup.array()
.when('loan_register', {
is: true,
then: yup.of(
yup.object().shape({
bank_name: yup.string().required(),
bank_reg_no: yup.string().required(),
loan_amount: yup.string().required(),
})
)
})
})

I think you'll want to utilize .when(). This allows exactly what you're looking for by providing conditional validation checks based off other attribute values.
It has a more explicit approach where you'd add
.when('loan_register', {is: true, then: /* yup schema */ })
I believe the change would look like
yup.object().shape({
loan_register: yup.boolean(),
loans: yup.array()
.when('loan_register', {
is: true,
then: yup.of(
yup.object().shape({
bank_name: yup.string().required(),
bank_reg_no: yup.string().required(),
loan_amount: yup.string().required(),
})
)
})
})

Yup: Ensure at least one of the elements in an array is valid

I have the following schema:
const baseSchema = {
name: Yup.array().of(
Yup.object().shape({
lang: Yup.string().required(),
value: Yup.string()
.min(2)
.max(20)
.required()
})
)
};
Is there a way to consider the schema valid if at least one of the objects in name is valid?
Edit: essentially it has to use when(), but what I'm struggling with is to find out how to check the other elements in the array.

You can use xor if you want one of them to be required:
const baseSchema = {
name: Yup.array().of(
Yup.object().shape({
lang: Yup.string().required().allow(""),
value: Yup.string()
.min(2)
.max(20)
.required().allow("")
})
)
};

How to validate that a string is not equal to another (blacklist) with Joi?

A classical example is:
schema = Joi.object().keys({
my_string: Joi.string().valid("myString").required()
});
This validate that object have field my_string which must have a myString as value.
How check that key my_string is not equal to notAllowedString?

you can use invalid to blacklist a value (link for ref)
schema = Joi.object().keys({
my_string: Joi.string().invalid("notAllowedString").required()
});
Here's a full example of how you would use it:
const Joi = require('joi');
const schema = Joi.object({
someIntA: Joi.number().integer().min(0).required(),
someIntB: Joi.number()
.integer()
.min(0)
.invalid(Joi.ref('someIntA'))
.required(),
someStringA: Joi.string().alphanum().min(3).max(30).required(),
someStringB: Joi.string()
.alphanum()
.min(3)
.max(30)
.invalid(Joi.ref('someStringA'))
.required(),
});