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Using Client-Side Only Packages

On occasion, you may need to use a function or library that only works client-side. This usually is because the library in question accesses something that isn’t available during server-side rendering (SSR), like browser DOM methods.

You’ll need to use one of the workarounds outlined below if your project fails to compile with gatsby develop or gatsby build with an error like:

Reference error: Window is not Defined

Workaround 1: Use a different library or approach

Sometimes the simplest approach is to work around the problem. If you can re-implement your component using a plugin which doesn’t break SSR, that’s probably best.

Workaround 2: Add client-side package via CDN

In the component where you need it, load the package via CDN using a <script /> tag.

To embed your script, you can:

  • Include it in a custom component as needed using react-helmet.
  • Add the script tag directly in your base HTML using Gatsby’s html.js

You should then follow React’s guidelines for Integrating with DOM Manipulation Plugins, using the methods available in the React Component Lifecycle to interact with the library you’re using.

import React, { Component } from "react"
import { Helmet } from "react-helmet"

class MyComponent extends Component {
  componentDidMount() {
    // set up and use external package as needed

  render(props) {
    return (
          <script src="https://cdn.example/path-to-external-library.js" />

        <h1>Hello World</h1>
        {/* etc */}

Workaround 3: Load client-side dependent components with loadable-components

Install loadable-components and use it as a wrapper for a component that wants to use a client-side only package.

npm install @loadable/component
# or use yarn
yarn add @loadable/component
import React, { Component } from "react"
import PropTypes from "prop-types"

import Loadable from "@loadable/component"

// these two libraries are client-side only
import Client from "shopify-buy"
import ShopifyBuy from "@shopify/buy-button-js"

const ShopifyBuyButton = props => {
  // custom component using shopify client-side libraries
  return <div>etc</div>

const LoadableBuyButton = Loadable(() => import("./ShopifyBuyButton"))

export default LoadableBuyButton

Workaround 4: Use React.lazy and Suspense on client-side only

React.lazy and Suspense are still not ready for server-side rendering, but they can still be used by checking that the code is executed only on the client. While this solution is inferior to loadable-components, that works both on server side and client, it still provides an alternative for dealing with client-side only packages, without an added dependency. Remember that the following code could break if executed without the isSSR guard.

import React from "react"

const ClientSideOnlyLazy = React.lazy(() =>
const MyPage = () => {
  const isSSR = typeof window === "undefined"

  return (
      {!isSSR && (
        <React.Suspense fallback={<div />}>
          <ClientSideOnlyLazy />

Note: There are other potential workarounds than those listed here. If you’ve had success with another method, check out the contributing docs and add yours!

If all else fails, you may also want to check out the documentation on Debugging HTML Builds.

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