#740·yup

[Question] Inconsistent behavior of .cast() and .validate() methods

Author: egorovliCreated Jan 8, 2020Updated Sep 26, 2025

Labelsbug

After reading the documentation, I had an impression that the following two snippets should yield the same result, provided the input is valid and doesn't throw:

javascript

let result = await schema.validate(input)

javascript

let result = schema.cast(input)

But consider the following example:

javascript

let schema = yup.object({
  price: yup.number()
    // Allow empty strings since I'm validating an HTML form where default
    // values for input[type=text] is an empty string
    .transform(value => isNaN(value) ? undefined : value)
})

let input = {
  price: ''
}

let result1 = await schema.validate(input) // {}
let result2 = schema.cast(input) // Uncaught TypeError: The value of price could not be cast to a value that satisfies the schema type: "number".

Is this the intended behavior? Thanks.

Source: jquense/yup

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