How to use apiClient generated by swagger-typescript-api

In previous post I described why and how you should generate TypeScript ApiClient based on Swagger . After that post you should have a generated a client, and now I will show use how to use it in a real project.

How to use it

We should not use the Generated Client directly. We should have a wrapper to be able to use it like that:

import { apiClient } from "~/apiClient";

export const getUserCards = async (
  getUserCardsParams: GetUserCardsParams
): Promise<UserCardDto[]> => {
  const response = await apiClient(({ api }) =>


Why like that?

  • I don’t want to care how to pass a base api url
  • I want to use use strong types
  • I don’t want to force other users of the api to know how it is implemented internally
    • They just use the wrapper
  • I want to have an abstraction between a generated client
    • to have a possibility to extend it if there is a need
    • to be secured for a situation when swagger-typescript-api won’t be supported
    • to simplify the usage of the api
    • because I want to have only one place in the code where generated client is created

How to write the wrapper

Look at at file where the wrapper is defined:


// I have generated it with `--axios` flag so I use axios here. 
import { AxiosRequestConfig, AxiosResponse } from "axios";
import { GeneratedApiClient, HttpClient } from "./GeneratedApiClient.generated";

// only this is exported. It is the only entry point to the api.
export const apiClient = async <ResponseType>(
    func: ApiClientOptions<ResponseType>
): Promise<AxiosResponse<ResponseType>> => {
    const apiClientInstance = createApiClient();
    const response = await func({
        api: apiClientInstance

    return response;

// it is the type of the function. What should be intput and output for passing function
type ApiClientOptions<ResponseType> = (
    apiClientParameters: ApiClientParameters
) => Promise<AxiosResponse<ResponseType>>;

// if you want to add more paramaters to the ApiClient, I think they should be defined here
type ApiClientParameters = {
    api: GeneratedApiClient<unknown>;

//it is the internal method method
const createApiClient = (): GeneratedApiClient<unknown> => {
    const baseUrl = getBaseUrl();

    // we need to configure it a bit on start. I mean we need to pass a `baseUrl` for example.
    const httpClient = new HttpClient({
        baseURL: baseUrl,
        headers: {
            "X-api-version": "1.0",
            "content-type": "application/json;charset=UTF-8",
    return new GeneratedApiClient(httpClient);

const getBaseUrl = () => {
    // you should replace it with getting an addres from your conifg
    return "httos://localhost:4444";

// It is a specific part of the generated client. It allows you to modify the request before sending if it secured. So you can add an `Authorization` header to it, for example.
const securityWorker = <SecurityDataType = unknown>(
    securityData: SecurityDataType | null
): AxiosRequestConfig => {
    const result: AxiosRequestConfig = {};
    const token = getAuthToken();
    result.headers = { Authorization: token };
    return result;

const getAuthToken = () => {
    return "{token_for_current_user}";

And thats all. Now you have everything to start using generated api client. You will never have typo in endpoint address or you will not pass wrong parameter, because everything is strongly typed.

Morover, the code is extensible. So when you need to change the bechavior of the apiClient, you can just do it. In the project where I am I did extensions like:

  • cancelable - to abort request if the same api method is invoke 2nd time. It is useful when a user change a search criteria
  • debounce - to do wait a bit before doing a request and wait if there is a newer version

Would you like to see thsese examples? Let me know in comment below.

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