Skip to content



❗⚠️❗ Warning:
These modifications will override the default behavior and configuration of TSDX. As such they can invalidate internal guarantees and assumptions. These types of changes can break internal behavior and can be very fragile against updates. Use with discretion!

TSDX uses Rollup under the hood. The defaults are solid for most packages (Formik uses the defaults!). However, if you do wish to alter the rollup configuration, you can do so by creating a file called tsdx.config.js at the root of your project like so:

// Not transpiled with TypeScript or Babel, so use plain Es6/Node.js!
module.exports = {
// This function will run for each entry/format/env combination
rollup(config, options) {
return config; // always return a config.

The options object contains the following:

export interface TsdxOptions {
// path to file
input: string;
// Name of package
name: string;
// JS target
target: 'node' | 'browser';
// Module format
format: 'cjs' | 'umd' | 'esm' | 'system';
// Environment
env: 'development' | 'production';
// Path to tsconfig file
tsconfig?: string;
// Is error extraction running?
extractErrors?: boolean;
// Is minifying?
minify?: boolean;
// Is this the very first rollup config (and thus should one-off metadata be extracted)?
writeMeta?: boolean;
// Only transpile, do not type check (makes compilation faster)
transpileOnly?: boolean;

Example: Adding Postcss

const postcss = require('rollup-plugin-postcss');
const autoprefixer = require('autoprefixer');
const cssnano = require('cssnano');
module.exports = {
rollup(config, options) {
plugins: [
preset: 'default',
inject: false,
// only write out CSS for the first bundle (avoids pointless extra files):
extract: !!options.writeMeta,
return config;


You can add your own .babelrc to the root of your project and TSDX will merge it with its own Babel transforms (which are mostly for optimization), putting any new presets and plugins at the end of its list.


You can add your own jest.config.js to the root of your project and TSDX will shallow merge it with its own Jest config.


You can add your own .eslintrc.js to the root of your project and TSDX will deep merge it with its own ESLint config.