getHeadersWithToken(token) {
        return {
            'Accept': 'application/json',
            'Content-Type': 'application/json',
            'dataType': 'json',
            'Authorization': `Bearer ${token}`
        }
    }

fetchPost(url, params, otherToken) {
        var fetchHeaders = this.headers
        if (otherToken) {
            fetchHeaders = this.getHeadersWithToken(otherToken)
        }

        var options = {
            headers: fetchHeaders,
            method: 'POST',
            body: JSON.stringify(params)
        }

        return fetch(url, options)
            .then(resp => {
                var json = resp.json()
                if (resp.ok || (resp.status == 401) || (resp.status == 400)) {
                    if (resp.statusText === 'Unauthorized') {
                        json.then(err => { throw err })
                    }

                    return json
                }

                return json.then(err => { throw err })

            })
            .catch(error => {
                throw error
            })
    }