wxt/docs/guide/resources/upgrading.md

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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.

v0.19.0 → v0.20.0

v0.20 is a big release! There are lots of breaking changes because this version is intended to be a release candidate for v1.0. If all goes well, v1.0 will be released with no additional breaking changes.

:::tip Read through all the changes once before making any code changes. :::

webextension-polyfill Removed

WXT no longer uses the webextension-polyfill!

Why? The polyfill doesn't add any value anymore. WXT's new browser supports the promise-based APIs on all browsers/manifest versions and all shared APIs behave the same way.

To upgrade, you have two options:

1. Stop using the polyfill - No changes necessary, though you may want to do some manual testing to make sure everything continues to work. None of the early testers of this feature reported any runtime issues once they stopped using the polyfill.
2. Continue using the polyfill - If you want to keep using the polyfill, you can! One less thing to worry about during this upgrade.
   • Install webextension-polyfill and WXT's new polyfill module:

     pnpm i webextension-polyfill @wxt-dev/webextension-polyfill
     

   • Add the WXT module to your config:

     export default defineConfig({
       modules: ['@wxt-dev/webextension-polyfill'],
     });
     

Regardless of your choice, the extensionApi config has been removed. Remove it from your wxt.config.ts file if present:

export default defineConfig({
  extensionApi: 'chrome', // [!code --]
});

Additionally, how you consume extension API types have changed. wxt/browser now uses types based on @types/chrome instead of @types/webextension-polyfill.

Types are now accessed off the Browser namespace:

import type { Runtime } from 'wxt/browser'; // [!code --]
import type { Browser } from 'wxt/browser'; // [!code ++]

function getMessageSenderUrl(sender: Runtime.MessageSender): string { // [!code --]
function getMessageSenderUrl(sender: Browser.runtime.MessageSender): string { // [!code ++]
  // ...
}

These new types contain up-to-date MV3 APIs, contain less bugs, and don't have any auto-generated names.

public/ and modules/ Directories Moved

The default location for the public/ and modules/ directories have changed to better align with standards set by other frameworks (Nuxt, Next, Astro, etc). Now, each path is relative to the project's root directory, not the src directory.

• If you follow the default folder structure, you don't need to make any changes.
• If you set a custom srcDir, you have two options:
  1. Keep the folders in the same place and update your project config:

     export default defineConfig({
       srcDir: 'src',
       publicDir: 'src/public', // [!code ++]
       modulesDir: 'src/modules', // [!code ++]
     });
     

  2. Move the your public/ and modules/ directories to the project root:

     <root>/
     +   modules/
     +   public/
         src/
             components/
             entrypoints/
     -       modules/
     -       public/
             utils/
         wxt.config.ts
     

Import Path Changes

The APIs exported by wxt/sandbox, wxt/client, or wxt/storage have moved to wxt/utils/*.

To upgrade, replace these imports with the new #imports module:

import { storage } from 'wxt/storage'; // [!code --]
import { defineContentScript } from 'wxt/sandbox'; // [!code --]
import { ContentScriptContext, useAppConfig } from 'wxt/client'; // [!code --]
import { storage } from '#imports'; // [!code ++]
import { defineContentScript } from '#imports'; // [!code ++]
import { ContentScriptContext, useAppConfig } from '#imports'; // [!code ++]

You can combine the imports into a single import statement, but it's easier to just find/replace each statement.

:::tip Before types will work, you'll need to run wxt prepare after installing v0.20 to generate the new TypeScript declarations. :::

Read more about the new #imports module in the blog post.

createShadowRootUi CSS Changes

WXT now resets styles inherited from the webpage (visibility, color, font-size, etc.) by setting all: initial inside the shadow root.

If you use createShadowRootUi:

1. Double check that your UI looks the same as before.

2. If you have any manual CSS resets to these styles, you can remove them. For example:

   body { /* [!code --] */
     /* Override Reddit's default "hidden" visibility on elements */ /* [!code --] */
     visibility: visible !important; /* [!code --] */
   } /* [!code --] */
   

:::warning This doesn't effect rem units. You should continue using postcss-rem-to-px or an equivalent library if the webpage sets the HTML element's font-size. :::

If you run into problems with the new behavior, you can disable it and continue using your current CSS:

const ui = await createShadowRootUi({
  inheritStyles: true, // [!code ++]
  // ...
});

Default Output Directories Changed

The default value for the outDirTemplate config has changed. Now, different build modes are output to different directories:

• --mode production → .output/chrome-mv3: Production builds are unchanged
• --mode development → .output/chrome-mv3-dev: Dev mode now has a -dev suffix so it doesn't overwrite production builds
• --mode custom → .output/chrome-mv3-custom: Other custom modes end with a -[mode] suffix

To use the old behavior, writing all output to the same directory, set outDirTemplate option:

export default defineConfig({
  outDirTemplate: '{{browser}}-mv{{manifestVersion}}', // [!code ++]
});

:::warning If you've previously loaded the extension into your browser manually for development, you'll need to uninstall and re-install it from the new dev output directory. :::

runner APIs Renamed

To improve consistency with the web-ext.config.ts filename, the "runner" API and config options have been renamed. You can continue using the old names, but they have been deprecated and will be removed in a future version:

1. The runner option has been renamed to webExt:

   export default defineConfig({
     runner: { // [!code --]
     webExt: { // [!code ++]
       startUrls: ["https://wxt.dev"],
     },
   });
   

2. defineRunnerConfig has been renamed to defineWebExtConfig:

   import { defineRunnerConfig } from 'wxt'; // [!code --]
   import { defineWebExtConfig } from 'wxt'; // [!code ++]
   

3. The ExtensionRunnerConfig type has been renamed to WebExtConfig

   import type { ExtensionRunnerConfig } from 'wxt'; // [!code --]
   import type { WebExtConfig } from 'wxt'; // [!code ++]
   

Deprecated APIs Removed

• entrypointLoader option: WXT now uses vite-node for importing entrypoints during the build process.

  This was deprecated in v0.19.0, see the v0.19 section for migration steps.

• transformManifest option: Use the build:manifestGenerated hook to transform the manifest instead:

  export default defineConfig({
    transformManifest(manifest) { // [!code --]
    hooks: { // [!code ++]
      'build:manifestGenerated': (_, manifest) => { // [!code ++]
         // ...
      }, // [!code ++]
    },
  });
  

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: () => ({ // [!code ++]
    ssr: { // [!code ++]
      noExternal: ['@webext-core/messaging', '@webext-core/proxy-service'], // [!code ++]
    }, // [!code ++]
  }), // [!code ++]
});

Read the full docs for more information.

:::details This change enables:

Importing variables and using them in the entrypoint options:

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:

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', // [!code ++]
});

:::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:

   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", { // [!code --]
const item = storage.defineItem<number | null>("local:count", { // [!code ++]
defaultValue: null, // [!code ++]
  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) => { // [!code --]
item.watch((newValue: number, oldValue: number) => { // [!code ++]
  // ...
});

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 // [!code --]
    popup.html
    popup.html
    popup.js // [!code ++]

v0.14.0 → v0.15.0

Renamed zip.ignoredSources to zip.excludeSources

export default defineConfig({
  zip: {
    ignoredSources: [
      /*...*/
    ], // [!code --]
    excludeSources: [
      /*...*/
    ], // [!code ++]
  },
});

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'; // [!code --]
  import { defineBackground, defineContentScript } from 'wxt/sandbox'; // [!code ++]
  

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": {
    // [!code ++]
    "lib": ["ESNext", "DOM", "WebWorker"] // [!code ++]
  } // [!code ++]
}

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.