some question about onDeleteClick method

[whois002]

onDeleteClick() {
this.props.deletePost(this.props.params.id)
.then(() => { this.context.router.push('/'); });
}

export function deletePost(id) {
const request = axios.delete(${ROOT_URL}/posts/${id}${API_KEY});

return {
type: DELETE_POST,
payload: request
};
}

The function "deletePost" does not return a promise. so why the "then" method in function "onDeleteClick" can direct call？