是的如何在同一个字段上获取字段 using.when 的值？

Question

How to get the value of field when using when on the same field?

  email: yup
    .string()
    .when([], {
      is: (val: string) => {
        console.log('val = ', val)
        return true
      },
      then: (schema) => {
        console.log('schema = ', schema)
        return schema
      },
    })
})

Answer 1

I am assuming you want to get the value of email in when condition at is location as well as at then location. then you have wrote everything correctly. just remove starting [] empty array in when condition. It you don't provide any array or string then value of current item will get at is location.

ref: React-hook-form validation when input is empty. Conflict with Yup.matches

I have updated the below as per your latest comment. I have tested this in my JavaScript file. so you might need to convert it as per TSX syntax.

email: yup
  .string()
  .when({
    is: (val) => {
      console.log('val = ', val)
      return true
    },
    then: yup.string()
      .test('testKey', 'error', (value) => console.log('value at then', value)),
  })
})