axios-get-json-response

A simple utility for checking status codes and parsing JSON data from Axios responses. While Axios can do this by itself, it doesn't document any distinguishable error types, and so when an error occurs you can never know what went wrong.

This library fixes that, by giving you two distinct error types. Hopefully this functionality eventually makes it into Axios itself.

Both error types correctly inherit from Error, and therefore a) have stacktraces, and b) can be used with instanceof as well as things based on it, like Bluebird's filtered .catch.

Examples

An existent and valid URL:

"use strict";
 
const axios = require("axios");
const Promise = require("bluebird");
const getJson = require("axios-get-json-response");
 
Promise.try(() => {
    return axios.get("http://cryto.net/test.json", getJson.axiosConfiguration); // {"hello": "world"}
}).then((response) => {
    let parsedJson = getJson.parse(response);
 
    console.log(parsedJson); // { hello: 'world' }
});

Using axios.create to set the custom configuration as a default, and showing the result for an existent URL that is not valid JSON:

"use strict";
 
const axios = require("axios");
const Promise = require("bluebird");
const getJson = require("axios-get-json-response");
 
let manualAxios = axios.create(getJson.axiosConfiguration);
 
Promise.try(() => {
    return manualAxios.get("http://cryto.net/invalid.json"); // {"hello": "world"
}).then((response) => {
    let parsedJson = getJson.parse(response);
    /* throws: ParsingFailed: Could not parse response body as JSON */
 
    console.log(parsedJson);
});

The result for a non-existent URL:

"use strict";
 
const axios = require("axios");
const Promise = require("bluebird");
const getJson = require("axios-get-json-response");
 
let manualAxios = axios.create(getJson.axiosConfiguration);
 
Promise.try(() => {
    return manualAxios.get("http://cryto.net/non-existent.json"); // URL does not exist
}).then((response) => {
    let parsedJson = getJson.parse(response);
    /* throws: BadResponseCode: Got an unexpected HTTP status code (404) */
 
    console.log(parsedJson);
});

API

getJson.axiosConfiguration

Some preset configuration options, that disable response code checking and body parsing in Axios. Needed for this library to work. These options are fed directly into Axios; see the example.

getJson.parse(response, [options])

Validates the status code and parses the response body. Returns the parsed JSON if successful, or throws either a BadStatusCode or ParsingFailed error depending on what went wrong (see below).

response: The Axios response object to handle.
options: Optional.
- validateStatus: Optional. A custom status code validation function, like in Axios. Defaults to the same as in Axios (all 2XX are considered valid). Expected to return true for a valid/expected status code, and false for an unexpected one.

getJson.BadStatusCode

An error type that signifies that an unexpected status code was received.

Extra properties on this error object:

statusCode: The received status code.

getJson.ParsingFailed

An error type that signifies that the response body could not be parsed as JSON.