Axios-layer NPM

Axios Layer

Middleware tool for extending basic axios functionality

Installation

npm i axios-layer
yarn add axios-layer

Problem

You need to add some complex functionality to axios, like router that make request to different domains dependent on environment or you need to add logging to axios, you also want to write tests on these modules and share them between projects

Usage

import axiosLayer from 'axios-layer';
import pino from 'pino';

const logger = pino();

const formatAxiosError = (error, options) => {
  // by default axios doesnt provide informative error object
  // so make a nice one
};

// makeRequest will call next layer or axios itself, you can call it several times
// options is AxiosRequestConfig object, it is optional
const loggerLayer = ({ logger }) => (makeRequest, options) => {
  logger.info(`Making request to ${options.url}, method: ${options.method}, data: ${options.data}`);

  // options are optional, they are passed by default,
  // use them if you need to change something in options object
  return makeRequest(options).catch((error) => {
    logger.error(formatAxiosError(error, options));

    return Promise.reject(error);
  });
};

axiosLayer.create({
  layers: [loggerLayer({ logger })],
});

Api

create(options)

Create a new instance or used provided and wrap it up in passed layers

Options:

Name	Type	Description	Default
layers	`AxiosLayer[]`	Array of AxiosLayer, this is the only required option
config	`AxiosRequestConfig`	Axios Config for creating new instance, peer axios dependency is used	`undefined`
axiosInstance	`AxiosInstance`	Axios Instance (to create instance use axios.create() method), peer axios dependency will be used by default to create axios instance	`axios.create(options.config)`

It returns ExtendableAxios, AxiosInstance with additional extend function on it:

type ExtendableAxios = AxiosInstance & {
  extend: {
    (...layers: AxiosLayer[]): ExtendableAxios;
    (config: AxiosRequestConfig): ExtendableAxios;
  };
};

You can create child instance but with some new functionality or with new AxioreRequestConfig

const transport = create({
  layers: [],
});

const childTransport = transport.extend({
  headers: {
    'x-test-header': '123',
  },
});

transport.get('/test') // wont have x-test-header
childTransport.get('/test') // will have x-test-header

AxiosLayer

type AxiosLayer = (
  makeRequest: (options?: Options) => Promise<any>,
  options: Options,
) => Promise<any>;

Layer should return a promise, you can omit options object in makeRequest()

wrapAxios(axios, ...layers)

function that axiosLayer.create() use inside, allows you to apply layers on axios instance

extendAxios(axios, ...layers)

same as wrap wrapAxios but doesn't mutate axios instance

Testing

check out /test directory in source code, there are two helpers that allows you to write unit and integration tests.

createAxiosMock creates axios instance with mock property that is just axios-mock-adapter

createTestServer creates server that will listen on free port and close it after test if you use .runTask function, also you can provide your own controller function