Python

    # myapp/ajax.py

    from adjax.registry import registry
    from adjax.utils.types import typed

    MESSAGE = 'Hello {who} and welcome to {where}'

    @registry.register
    @typed(strict=True)
    def visit(request, where: str, who: str) -> dict:
        """Visit the specified lands."""

        return {
            'who': who,
            'where': where,
            'message': MESSAGE.format(who=who, where=where),
        }

        

    // static/example.js

    ADJAX.apps.myapp.visit('Vinland', 'Leif', function (data) {
        data == {
            who: "Leif",
            where: "Vinland",
            message: "Hello Leif and welcome to Vinland"
        }
    });

    ADJAX.apps.myapp.visit(33, 42, function (data) {
        data == {
            error: true,
            message: "Value 42 of type class (...)"
        }
    });