fetch(this.props.url, {
    method: 'POST',
    body: JSON.stringify({
        class: 'property',
        action: 'view',
        objectId: this.props.element.id,
        token: this.props.token,
    }),
})
    .then(response => response.json())
    .then(json => {
        this.setState({
            property: json.property
        });
        console.log(json);
    })

{
        property: {
            units: {
                {
                    id: 31,
                    ...
                },
                {
                    id: 33,
                    ...
                }
            }
        }
    }

property: {
        units: {
            {
                id: 33,
                ...
            },
            {
                id: 33,
                ...
            }
        }
    }
}