createAxiosExecutor(instanceOrFactory, options?) — @routar/axios

Accepts an AxiosInstance (CSR) or a factory function that returns one (SSR).

import axios from 'axios'
import { createAxiosExecutor } from '@routar/axios'
 
// CSR — shared instance
const executor = createAxiosExecutor(axios.create({ baseURL: 'https://api.example.com' }))

Instance vs. factory

// CSR — pass the instance directly
const executor = createAxiosExecutor(axios.create({ baseURL: BASE_URL }))
 
// SSR — factory, called per-request for fresh headers
const executor = createAxiosExecutor(async () => {
  const token = await getServerToken()
  return axios.create({
    baseURL: BASE_URL,
    headers: { Authorization: `Bearer ${token}` },
  })
})

The factory form is called on every request, making it safe for per-request auth headers in SSR environments.

Options

Errors

HTTP failures are normalized to HttpError (from @routar/core), the same type the fetch executor throws — so callers and onError plugins stay transport-agnostic. The original AxiosError is preserved on err.cause:

import { HttpError } from '@routar/core'
import { isAxiosError } from 'axios'
 
try {
  await todoApi.getDetail({ path: { id: 999 } })
} catch (err) {
  if (err instanceof HttpError) {
    console.log(err.status)     // 404
    console.log(err.statusText) // 'Not Found'
    console.log(err.body)       // server error body
 
    // Axios-specific fields remain available via `cause`
    if (isAxiosError(err.cause)) {
      console.log(err.cause.config) // request config
      console.log(err.cause.code)   // e.g. 'ERR_BAD_REQUEST'
    }
  }
}

Errors without a response (network failures, request cancellations) are re-thrown unchanged as the original AxiosError, since there is no HTTP status to normalize.

Query parameter serialization

Axios serializes array params using its own default (ids[]=1&ids[]=2), while createFetchExecutor uses repeated keys (ids=1&ids=2). If your server is sensitive to array format and you switch executors, update your server-side parsing accordingly.

Instance detection

createAxiosExecutor distinguishes an AxiosInstance from a factory function via duck-typing: it checks for both the interceptors property and a request method. AxiosInstance objects always have both; plain factory functions do not.