How to use on reference input to related filed in react-admin?

I'm using react-admin.

I have 3 resources: schools, teachers and classes

Each school has its teachers and its classes
Each class has a teacher from its school

In creations of class one of the inputs is a teacher, it is need to be a reference type but not to all the teachers only for those who belong to the school of this class.

How should I support it?

How to pass the school_id to the reference input?

Thank you!

Solution

This is explained in the documentation: https://marmelab.com/react-admin/Inputs.html#referenceinput

In summary:

/ you can filter the query used to populate the possible values. Use the
// `filter` prop for that.
<ReferenceInput
    source="teacher_id"
    reference="teachers"
    filter={{ school_id: values.school_id }}
>
    <SelectInput optionText="name" />
</ReferenceInput>

You may wonder how you can get this school_id: https://marmelab.com/react-admin/Inputs.html#linking-two-inputs

import { useFormState } from 'react-final-form';

const TeacherInput = () => {
    const { values } = useFormState();

    return (
        <ReferenceInput
            source="teacher_id"
            reference="teachers"
            filter={{ school_id: school_id: values.school_id }}
        >
            <SelectInput optionText="name" />
        </ReferenceInput>
    );
}