Axios Verror

Enhance Axios request errors using VError.

Installation

npm install @centrapay/axios-verror

Usage

Handle axios errors with AxiosVError.enhance:

axios.request(args).catch(AxiosVError.enhance);

Error will be rethrown as a VError with a better error message and with VError.info() populated with structured details about the error.

Complete Example

const AxiosVError = require('@centrapay/axios-verror');
const axios = require('axios');

async function callApi(data) {
  await axios.request({
    url: 'http://myhost/',
    method: 'POST',
    data,
  }).catch(AxiosVError.enhance);
}

Handling Enhanced Errors

try {
  await callApi({ msg: 'hello' });
}
catch (e) {
  if (VError.info(e).axios?.status == 421) {
    // handle rate limit
  }
}

VError Info

Structured details about the error can be extracted with VError.info(err).axios. An object with the following properties will be provided:

Name	Type	Description
method	String	HTTP request method (GET, POST etc).
url	String	HTTP request URL. Query params not included when defined as Axios "params".
status	Number (Optional)	HTTP response status code.
message	String (Optional)	Extracted HTTP response message. See `extractMessage()` option to customize.
res	Object (Optional)	Raw Axios response object. See Axios Response Schema.

Only the requested method and URL are guaranteed to be present. Other properties require a response. Whether a response is available depends on the underlying error. For example, if there is a network connectivity issue then there will not be an HTTP response available.

Error Messages

Axios error messages normally only provide an HTTP status code. This, presumably, prevents Axios leaking potentially sensitive details into logs, such as host names or path parameters, but it makes debugging errors difficult. Example Axios error message:

Request failed with status code 400

Enhanced error messages include status, method, URL and a formatted message extracted from the response. Example enhanced message:

[400] POST https://host/ (invalid request): Request failed with status code 400

Customizing

Create a modified instance of AxiosVError with AxiosVError.configure():

const axiosVError = AxiosVError.configure({
  extractMessage: res => res?.data?.error_code
});
axios.request(args).catch(axiosVError.enhance);

AxiosVError instances can be reused.

Options

The following options are available for configuring AxiosVError behavior.

extractMessage(res)

A function which extracts the error message from the axios response. By default, the message will be attempted to be taken from the parsed Axios response body as either res.data.message or res.data.error.message.

formatSummary({ status, method, url, message })

A function which generates the formatted error message. By default, the message will be formatted like:

`[${status}] ${method} ${url} (${message})`

History

See Changelog

Legal

This software is licensed under Apache-2.0 License. Please see LICENSE for details.