I'm trying to require one of two checkboxes to be selected in a form. The following doesn't seem to work according to the documentation:

yearGroups: yup.object().shape({
          primary: yup.bool().when('yearGroups.primary', {
            is: false,
            then: yup
              .bool()
              .oneOf([true], '')
              .required()
          }),
          secondary: yup.bool().when('yearGroups.secondary', {
            is: false,
            then: yup
              .bool()
              .oneOf([true], '')
              .required()
          }),
        }),

I'm trying to require one of two checkboxes to be selected in a form. The following doesn't seem to work according to the documentation:

yearGroups: yup.object().shape({
          primary: yup.bool().when('yearGroups.primary', {
            is: false,
            then: yup
              .bool()
              .oneOf([true], '')
              .required()
          }),
          secondary: yup.bool().when('yearGroups.secondary', {
            is: false,
            then: yup
              .bool()
              .oneOf([true], '')
              .required()
          }),
        }),

• javascript
• reactjs
• react-hook-form
• yup

• Do you have any error message? – NearHuscarl Commented Oct 4, 2021 at 11:45
• no, I just don't get the validation I require @NearHuscarl – user15973342 Commented Oct 4, 2021 at 11:49

2 Answers 2

Try this one. See the explanation here:

const schema = yup.object().shape({
  yearGroups: yup.object().shape(
    {
      primary: yup.bool().when("secondary", {
        is: (secondary) => !secondary,
        then: yup.bool().oneOf([true], "At least one needs to be checked")
      }),
      secondary: yup.bool().when("primary", {
        is: (primary) => !primary,
        then: yup.bool().oneOf([true], "At least one needs to be checked")
      })
    },
    [
      ["primary", "secondary"],
      ["secondary", "primary"]
    ]
  )
});

Live Demo

This is some kind of duplication, but here are solutions: using .test() function or create your own Method - .addMethod

1. .test function, example here
2. .addMethod function, example here

I am using .addMethod in my code, it's more flexible, you can define all params you need. Once you defined it in the file, you can call it everywhere you need.