How to solve the document is not defined error

May 4, 2022

Learn how to fix the 'document is not defined' error in Node.js or Next.js: document is browser-only, so guard it with a typeof window check.

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Here’s how to fix the “referenceerror: document is not defined” error that you might have in Node.js or with a tool like Next.js.

document is an object that’s made available by the browser, and it’s not available in a server-side JavaScript environment.

I describe the document object is details in my extensive DOM Document Object Model guide.

With Node.js in particular there’s no way to workaround the problem - you must find the particular place where document is used, and revisit the code to figure out why you are accessing the document object.

You are running frontend code in a backend environment.

In Next.js you can fix this problem by wrapping the code you run in a conditional.

The code might be running in both situations - frontend, when you navigate to a page using a link, and server-side if you require server-side into your page, for example by running getServerSideProps().

In this case, you can limit the reference to document into a conditional that checks if the window object is available, like this:

if (typeof window !== 'undefined') {
  //here `window` is available, so `window.document` (or simply `document`) is available too
}

And this will fix your problem, since you only run anything inside the conditional in a browser environment.

Tagged: JavaScript · All topics

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