How throw multiple errors in duplicate check?

This code only throw first duplicate case. I need show all duplicated errors.

yup.addMethod(yup.array, 'unique', function(message, path) {
  return this.test('unique', message, function(list) {
    const duplicates = list
      .map(r => r[path])
      .filter((value, index, self) => self.indexOf(value) !== index);
    if (duplicates.length == 0) return true;

    // find first duplicated.
    list.forEach((row, index) => {
      if (_.includes(duplicates, row[path])) {
        throw this.createError({
          path: `${this.path}[${index}].${path}`,
          message,
        });
      }
    });

    return true;
  });
});
...
const myValidation = yup.object().shape({
  people: yup
    .array()
    .of(
      yup.object().shape(
        _.reduce(
          _.filter(Columns, col => col.validator),
          (result, col) => {
            mixin(result, {
              [col.id]: col.validator,
            });
            return result;
          },
          {},
        ),
      ),
    )
    .unique('email duplicated..', 'email')
});

I used https://github.com/jquense/yup/issues/345 as reference.

[AlexLomm]

@jquense could you provide an example illustrating how this should be done?

I tried returning an array of errors, but it didn’t work. I believe this happens because the returned array is treated as a “truthy” value, hence the validation is considered passed.

Throwing the array works, however it interrupts other validations despite the { abortEarly: false } option being set.

Is there any way to avoid these problems?

[AlexLomm]

Per my original question:

@jquense could you provide an example illustrating how this should be done?

I tried returning an array of errors, but it didn’t work. I believe this happens because the returned array is treated as a “truthy” value, hence the validation is considered passed.

Throwing the array works, however it interrupts other validations despite the { abortEarly: false } option being set.

Is there any way to avoid these problems?

I ended up implementing a custom validation function that checks if there are any siblings with the same value in its parent array for each object. This allows us to perform checks from the objects’ “perspective”, rather than from the array’s perspective. This is useful because it lets us have multiple errors of the same kind by “tying” them to their respective objects. Example:

import { string, array, object } from "yup";

const people = [
  { name: "John Doe", email: "[e-mail]" }, // duplicate email
  { name: "Jane Smith", email: "[e-mail]" },
  { name: "Jon Snow", email: "[e-mail]" } // duplicate email
];

const personSchema = object({ name: string(), email: string() }).test(
  "unique",
  "Emails must be unique.",
  function validateUnique(currentPerson) {
    const otherPeople = this.parent.filter(person => person !== currentPerson);

    const isDuplicate = otherPeople.some(
      otherPerson => otherPerson.email === currentPerson.email
    );

    return isDuplicate
      ? this.createError({ path: `${this.path}.email` })
      : true;
  }
);

const peopleSchema = array().of(personSchema);

try {
  // throws an error because there are two people
  // with the same "[e-mail]" email in the array
  peopleSchema.validateSync(people, { abortEarly: false });
} catch (error) {
  console.log(JSON.stringify(error, null, 2));
}

Check the CodeSandbox snippet