Pay attention
This documentation is for the as yet unreleased version of effector Spacewatch 23.0.

Babel plugin

[ ru ]

Built-in plugin for babel can be used for ssr and debugging. It inserts a name a Unit, inferred from variable name and sid (stable identifier), computed from the location in the source code.

For example, in case effects without handlers, it improves error messages by clearly showing in which effect error happened.

import { createEffect } from "effector";

const fetchFx = createEffect();


// => no handler used in fetchFx

Try it


In the simplest case, it can be used without any configuration:

// .babelrc
  "plugins": ["effector/babel-plugin"]


Stable hash identifier for events, effects, stores and domains, preserved between environments, to handle client-server interaction within the same codebase.

The crucial value of sid is that it can be autogenerated by effector/babel-plugin with default config, and it will be stable between builds.

See example project

// common.js
import { createEffect } from "effector";

export const getUser = createEffect({ sid: "GET /user" });
// => GET /user
// worker.js
import { getUsers } from "./common.js";

getUsers.use((userID) => fetch(userID));{ result }) => {
  postMessage({ sid: getUsers.sid, result });

onmessage = async ({ data }) => {
  if (data.sid !== getUsers.sid) return;
// client.js
import { createEvent } from "effector";
import { getUsers } from "./common.js";

const onMessage = createEvent();

const worker = new Worker("worker.js");
worker.onmessage = onMessage;

  (userID) =>
    new Promise((rs) => {
      worker.postMessage({ sid: getUsers.sid, userID });
      const unwatch ={ data }) => {
        if (data.sid !== getUsers.sid) return;



  • Type: string | string[]
  • Default: ['effector', 'effector/compat']

Specifying import name or names to process by plugin. Import should be used in the code as specified.


  • Type: string[]

Accepts an array of module names which exports treat as custom factories, therefore, each function call provides a unique prefix for sids of units inside them. Used to SSR(Server Side Rendering) and itโ€™s not required for client-only application.

  • Factories can have any number of arguments.
  • Factories can create any number of units.
  • Factories can call any effector methods.
  • Factories can call other factories from other modules.
  • Modules with factories can export any number of functions.
  • Factories should be compiled with effector/babel-plugin as well as code which use them.


// .babelrc
  "plugins": [
        "factories": ["src/createEffectStatus", "~/createCommonPending"]
// ./src/createEffectStatus.js
import { rootDomain } from "./rootDomain";

export function createEffectStatus(fx) {
  const $status = rootDomain.createStore("init").on(fx.finally, (_, { status }) => status);

  return $status;
// ./src/statuses.js
import { createEffectStatus } from "./createEffectStatus";
import { fetchUserFx, fetchFriendsFx } from "./api";

export const $fetchUserStatus = createEffectStatus(fetchUserFx);
export const $fetchFriendsStatus = createEffectStatus(fetchFriendsFx);

Import createEffectStatus from './createEffectStatus' was treated as factory function, so each store created by it has its own sid and will be handled by serialize independently, although without factories they will share the same sid.


  • Type: boolean
  • Default: false

Replaces imports from effector-react to effector-react/scope. Useful for building both server-side and client-side builds from the same codebase.


  • Type: boolean
  • Default: true

Adds name to units factories call. Useful for minification and obfuscation of production builds.


  • Type: boolean
  • Default: false

Adds location to methodsโ€™ calls. Used by devtools, for example effector-logger.


  • Type: boolean
  • Default: false

Adds a file path and variable name of a unit definition to a sid. Useful for debugging SSR.


  • Type: boolean
  • Default: false

Option for effector/babel-plugin for making custom unit factories with clean configuration.

// .babelrc
  "plugins": [
    ["effector/babel-plugin", { "addLoc": true }],
        "importName": "@lib/createInputField",
        "storeCreators": ["createInputField"],
        "noDefaults": true
// @lib/createInputField.js
import { createStore } from "effector";
import { resetForm } from "./form";

export function createInputField(defaultState, { sid, name }) {
  return createStore(defaultState, { sid, name }).reset(resetForm);
// src/state.js
import { createInputField } from "@lib/createInputField";

const foo = createInputField("-");

will be treated as store creator and compiled to

const foo = createInputField('-', {
  name: 'foo',
  sid: 'z&si65'



Vite + React (SSR)

To use with effector/babel-plugin, you have to following next steps:

  1. Install @vitejs/plugin-react package.
  2. vite.js.config should be follows:

Note: effector/babel-plugin is not a package, it is bundled with effector

// vite.config.js
import { defineConfig } from "vite";
import react from "@vitejs/plugin-react";

export default defineConfig({
  plugins: [
      babel: {
        plugins: ["effector/babel-plugin"],
        // Use .babelrc files
        babelrc: true,
        // Use babel.config.js files
        configFile: true,