How to set dynamic error messages in Yup async validation?

user_5271656 0
Viewed 21620

I am trying async validation in Formik using Yup's .test() method and need to set the error message that I get from the API. Error messages are going to be different based on some conditions in backend.

Tried few solutions mentioned here
https://github.com/jquense/yup/issues/222 and Dynamic Validation Messages Using Yup and Typescript

But Yup is throwing the default error message given in test().

Documentation says that

All tests must provide a name, an error message and a validation function that must return true or false or a ValidationError. To make a test async return a promise that resolves true or false or a ValidationError.

I am resolving a new ValidationError with the error message but still, it throws the default error.

Here is the code.

const schema = Yup.object().shape({
  email: Yup.string().test(
    "email_async_validation",
    "Email Validation Error", // YUP always throws this error
    value => {
      return new Promise((resolve, reject) => {
        emailValidationApi(value)
          .then(res => {
            const { message } = res.data; // I want this error message to be shown in form.
            resolve(new Yup.ValidationError(message));
          })
          .catch(e => {
            console.log(e);
          });
      });
    }
  )
});
yup formik reactjs
4 Answers

I got it working using the function syntax instead of arrow function for validation function.

Doc says:

test functions are called with a special context, or this value, that exposes some useful metadata and functions. Note that to use this context, the test function must be a function expression (function test(value) {}), not an arrow function, since arrow functions have lexical context.

Here is the working code.

const schema = Yup.object().shape({
  email: Yup.string()
    .email("Not a valid email")
    .required("Required")
    .test("email_async_validation", "Email Validation Error", function (value) { // Use function
      return emailValidationApi(value)
        .then((res) => {
          const message = res;
          console.log("API Response:", message);
          return this.createError({ message: message });
          // return Promise.resolve(this.createError({ message: message })); // This also works
        })
        .catch((e) => {
          console.log(e);
        });
    })
});
user_52716560

Actually you're almost correct.You just need to use the following:

resolve(this.createError({ message: message }));

Let me know if it still doesn't work ya

user_91328510

I am able to do this with arrow function also.

const schema = Yup.object().shape({
 email: Yup.string()
  .email("Not a valid email")
  .required("Required")
  .test("email_async_validation", "Email Validation Error", (value, {createError}) { 
    return emailValidationApi(value)
      .then((res) => {
        const message = res;
        console.log("API Response:", message);
        return createError({ message: message });
      })
      .catch((e) => {
        console.log(e);
      });
    })
  });
user_53499170

Don't pass second parameter, as we generally pass it as a error message instead create your own custom message using "createError" and return it on your condition.

import * as yup from "yup";

const InitiateRefundSchema = yup.object().shape({
  amountPaid: yup.number(),
  refundAmount: yup
    .number()
    .test("test-compare a few values", function (value) {
      let value1 = this.resolve(yup.ref("amountPaid"));
      let value2 = this.resolve(yup.ref("refundAmount"));
      if (value1 < value2) {
        return this.createError({
          message: `refund amount cannot be greater than paid amount '${value1}'`,
          path: "refundAmount", // Fieldname
        });
      } else return true;
    }),
})
user_142072000
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