Function intern_delete

docs/app/js/sanddance-app.js:110732–110739

({ _intern , _key  }, value)

    return value;
}
function intern_delete({ _intern , _key  }, value) {
    const key = _key(value);
    if (_intern.has(key)) {
        value = _intern.get(value);
        _intern.delete(key);
    }
    return value;
}
function keyof(value) {
    return value !== null && typeof value === "object" ? value.valueOf() : value;
}