Upgrading WXT

Overview

To upgrade WXT to the latest version... just install it!

pnpm i wxt@latest

Listed below are all the breaking changes you should address when upgrading to a new version of WXT.

Currently, WXT is in pre-release. This means changes to the second digit, v0.X, are considered major and have breaking changes. Once v1 is released, only major version bumps will have breaking changes.

v0.18.5 → v0.19.0

vite-node Entrypoint Loader

The default entrypoint loader has changed to vite-node. If you use any NPM packages that depend on the webextension-polyfill, you need to add them to Vite's ssr.noExternal option:

export default defineConfig({
  vite: () => ({ 
    ssr: { 
      noExternal: ['@webext-core/messaging', '@webext-core/proxy-service'], 
    }, 
  }), 
});

Read the full docs for more information.

This change enables:

Importing variables and using them in the entrypoint options:

// entrypoints/content.ts
import { GOOGLE_MATCHES } from '~/utils/constants'

export default defineContentScript({
  matches: [GOOGLE_MATCHES],
  main: () => ...,
})

Using Vite-specific APIs like import.meta.glob to define entrypoint options:

// entrypoints/content.ts
const providers: Record<string, any> = import.meta.glob('../providers/*', {
  eager: true,
});

export default defineContentScript({
  matches: Object.values(providers).flatMap(
    (provider) => provider.default.paths,
  ),
  async main() {
    console.log('Hello content.');
  },
});

Basically, you can now import and do things outside the main function of the entrypoint - you could not do that before. Still though, be careful. It is recommended to avoid running code outside the main function to keep your builds fast.

To continue using the old approach, add the following to your wxt.config.ts file:

export default defineConfig({
  entrypointLoader: 'jiti', 
});

WARNING

entrypointLoader: "jiti" is deprecated and will be removed in the next major version.

Drop CJS Support

WXT no longer ships with Common JS support. If you're using CJS, here's your migration steps:

1. Add "type": "module" to your package.json.
2. Change the file extension of any .js files that use CJS syntax to .cjs, or update them to use EMS syntax.

Vite also provides steps for migrating to ESM. Check them out for more details: https://vitejs.dev/guide/migration#deprecate-cjs-node-api

v0.18.0 → v0.18.5

When this version was released, it was not considered a breaking change... but it should have been.

New modules/ Directory

WXT now recognizes the modules/ directory as a folder containing WXT modules.

If you already have <srcDir>/modules or <srcDir>/Modules directory, wxt prepare and other commands will fail.

You have two options:

1. [Recommended] Keep your files where they are and tell WXT to look in a different folder:

   // wxt.config.ts
   export default defineConfig({
     modulesDir: 'wxt-modules', // defaults to "modules"
   });

2. Rename your modules directory to something else.

v0.18.0 → v0.18.5

When this version was released, it was not considered a breaking change... but it should have been.

New modules/ Directory

WXT now recognizes the modules/ directory as a folder containing WXT modules.

If you already have <srcDir>/modules or <srcDir>/Modules directory, wxt prepare and other commands will fail.

You have two options:

1. [Recommended] Keep your files where they are and tell WXT to look in a different folder:

   // wxt.config.ts
   export default defineConfig({
     modulesDir: 'wxt-modules', // defaults to "modules"
   });

2. Rename your modules directory to something else.

v0.17.0 → v0.18.0

Automatic MV3 host_permissions to MV2 permissions

Out of an abundance of caution, this change has been marked as a breaking change because permission generation is different.

If you list host_permissions in your wxt.config.ts's manifest and have released your extension, double check that your permissions and host_permissions have not changed for all browsers you target in your .output/*/manifest.json files. Permission changes can cause the extension to be disabled on update, and can cause a drop in users, so be sure to double check for differences compared to the previous manifest version.

v0.16.0 → v0.17.0

Storage - defineItem Requires defaultValue Option

If you were using defineItem with versioning and no default value, you will need to add defaultValue: null to the options and update the first type parameter:

const item = storage.defineItem<number>("local:count", { 
const item = storage.defineItem<number | null>("local:count", { 
defaultValue: null, 
  version: ...,
  migrations: ...,
})

The defaultValue property is now required if passing in the second options argument.

If you exclude the second options argument, it will default to being nullable, as before.

const item: WxtStorageItem<number | null> =
  storage.defineItem<number>('local:count');
const value: number | null = await item.getValue();

Storage - Fix Types In watch Callback

If you don't use TypeScript, this isn't a breaking change, this is just a type change.

const item = storage.defineItem<number>('local:count', { defaultValue: 0 });
item.watch((newValue: number | null, oldValue: number | null) => { 
item.watch((newValue: number, oldValue: number) => { 
  // ...
});

v0.15.0 → v0.16.0

Output Directory Structure Changed

JS entrypoints in the output directory have been moved. Unless you're doing some kind of post-build work referencing files, you don't have to make any changes.

.output/
  <target>/
    chunks/
      some-shared-chunk-<hash>.js
      popup-<hash>.js
    popup.html
    popup.html
    popup.js

v0.14.0 → v0.15.0

Renamed zip.ignoredSources to zip.excludeSources

// wxt.config.ts
export default defineConfig({
  zip: {
    ignoredSources: [
      /*...*/
    ], 
    excludeSources: [
      /*...*/
    ], 
  },
});

Renamed Undocumented Constants

Renamed undocumented constants for detecting the build config at runtime in #380. Now documented here: https://wxt.dev/guide/multiple-browsers.html#runtime

• __BROWSER__ → import.meta.env.BROWSER
• __COMMAND__ → import.meta.env.COMMAND
• __MANIFEST_VERSION__ → import.meta.env.MANIFEST_VERSION
• __IS_CHROME__ → import.meta.env.CHROME
• __IS_FIREFOX__ → import.meta.env.FIREFOX
• __IS_SAFARI__ → import.meta.env.SAFARI
• __IS_EDGE__ → import.meta.env.EDGE
• __IS_OPERA__ → import.meta.env.OPERA

v0.13.0 → v0.14.0

Content Script UI API changes

createContentScriptUi and createContentScriptIframe, and some of their options, have been renamed:

• createContentScriptUi({ ... }) → createShadowRootUi({ ... })
• createContentScriptIframe({ ... }) → createIframeUi({ ... })
• type: "inline" | "overlay" | "modal" has been changed to position: "inline" | "overlay" | "modal"
• onRemove is now called before the UI is removed from the DOM, previously it was called after the UI was removed
• mount option has been renamed to onMount, to better match the related option, onRemove.

v0.12.0 → v0.13.0

New wxt/storage APIs

wxt/storage no longer relies on unstorage. Some unstorage APIs, like prefixStorage, have been removed, while others, like snapshot, are methods on the new storage object. Most of the standard usage remains the same. See https://wxt.dev/guide/storage and https://wxt.dev/api/reference/wxt/storage/ for more details (#300)

v0.11.0 → v0.12.0

API Exports Changed

defineContentScript and defineBackground are now exported from wxt/sandbox instead of wxt/client. (#284)

• If you use auto-imports, no changes are required.
• If you have disabled auto-imports, you'll need to manually update your import statements:

  import { defineBackground, defineContentScript } from 'wxt/client'; 
  import { defineBackground, defineContentScript } from 'wxt/sandbox'; 

v0.10.0 → v0.11.0

Vite 5

You will need to update any other Vite plugins to a version that supports Vite 5.

v0.9.0 → v0.10.0

Extension Icon Discovery

WXT no longer discovers icons other than .png files. If you previously used .jpg, .jpeg, .bmp, or .svg, you'll need to convert your icons to .png files or manually add them to the manifest inside your wxt.config.ts file.

v0.8.0 → v0.9.0

Removed WebWorker Types by Default

Removed "WebWorker" types from .wxt/tsconfig.json. These types are useful for MV3 projects using a service worker.

To add them back to your project, add the following to your project's TSConfig:

{
  "extends": "./.wxt/tsconfig.json",
  "compilerOptions": {

    "lib": ["ESNext", "DOM", "WebWorker"] 
  } 
}

v0.7.0 → v0.8.0

defineUnlistedScript

Unlisted scripts must now export default defineUnlistedScript(...).

BackgroundDefinition Type

Rename BackgroundScriptDefintition to BackgroundDefinition.

v0.6.0 → v0.7.0

Content Script CSS Output Location Changed

Content script CSS used to be output to assets/<name>.css, but is now content-scripts/<name>.css to match the docs.

v0.5.0 → v0.6.0

Require a Function for vite Config

The vite config option must now be a function. If you were using an object before, change it from vite: { ... } to vite: () => ({ ... }).

v0.4.0 → v0.5.0

Revert Move Public Directory

Change default publicDir to from <rootDir>/public to <srcDir>/public.

v0.3.0 → v0.4.0

Update Default Path Aliases

Use relative path aliases inside .wxt/tsconfig.json.

v0.2.0 → v0.3.0

Move Public Directory

Change default publicDir to from <srcDir>/public to <rootDir>/public.

Improve Type Safety

Add type safety to browser.runtime.getURL.

v0.1.0 → v0.2.0

Rename defineBackground

Rename defineBackgroundScript to defineBackground.