BREAKING CHANGE: Switch from using `jiti` to import entrypoints during the build process by default to `vite-node`.
To continue using `jiti`, add the following to your `wxt.config.ts` file:
```ts
export default defineConfig({
entrypointLoader: "jiti",
})
```
NOTE: "jiti" is deprecated and will be removed in the next major version, `v0.20.0`.
BREAKING CHANGE: Out of an abundance of caution, I've marked this as a breaking change because permission generation has changed. ***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. 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.
BREAKING CHANGE: The build output has changed slightly. This isn't a huge deal, and no steps are required for users unless you're doing something weird with the output files after a build.
Before:
```
.output/
<target>/
chunks/
popup-<hash>.js
popup.html
```
After:
```
.output/
<target>/
popup.html
popup.js
```
This applies for all HTML files, not just the popup.
BREAKING CHANGES: Several APIs/options have been renamed:
- `type: "inline" | "overlay" | "modal"` has been changed to `position: "inline" | "overlay" | "modal"`
- `createContentScriptUi({ ... })` → `createShadowRootUi({ ... })`
- `createContentScriptIframe({ ... })` → `createIframeUi({ ... })`
- `onRemove` is now called ***before*** the UI is removed from the DOM, previously it was called after the UI was removed
BREAKING CHANGE: `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.
BREAKING CHANGE: `defineContentScript` and `defineBackground` are now exported from `wxt/sandbox` instead of `wxt/client`. If you use auto-imports, no changes are required. If you have disabled auto-imports, you'll need to manually update your import statements.
BREAKING CHANGE: No longer discover icons with extensions other than `.png`. 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.
A clear and concise description of what the bug is.
### To Reproduce
Upload a ZIP or share a link to a repo representing the minimal reproduction. **_If you don't upload a minimal reproduction, you bug report will be closed._**
Steps to reproduce the behavior:
1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error
### Expected behavior
A clear and concise description of what you expected to happen.
### Screenshots
If applicable, add screenshots to help explain your problem.
### Environment
<!--- Run `npx envinfo --system --browsers --binaries --npmPackages wxt,vite` and paste the output below -->
```
Paste output here
```
### Additional context
Add any other context about the problem here, otherwise you can delete this section.
Thanks for taking the time to fill out this bug report!
- type:textarea
id:bug-description
attributes:
label:Describe the bug
description:A clear and concise description of what the bug is. If you intend to submit a PR for this issue, tell us in the description. Thanks!
placeholder:I am doing ... What I expect is ... What actually happening is ...
validations:
required:true
- type:textarea
id:reproduction
attributes:
label:Reproduction
description:|
Please provide a minimal reproduction. This can include:
- A PR with a failing test case
- A link to a github repo
- A ZIP you upload to this issue
A [minimal reproduction](https://stackoverflow.com/help/minimal-reproducible-example) is required ([Why?](https://antfu.me/posts/why-reproductions-are-required)). If a report is vague (e.g. just a generic error message) and has no reproduction or a partial reproduction, it will be closed immediately and labeled with as "needs-reproduction". Once a reproduction is provided, it will be re-opened.
placeholder:Reproduction URL or attach a ZIP
validations:
required:true
- type:textarea
id:reproduction-steps
attributes:
label:Steps to reproduce
description:Please provide any reproduction steps that may need to be described. E.g. if it happens only when running the dev or build script make sure it's clear which one to use.
placeholder:Run `npm install` followed by `npm run dev`
- type:textarea
id:system-info
attributes:
label:System Info
description:Output of `npx envinfo --system --browsers --binaries --npmPackages wxt,vite`
render:shell
placeholder:System, Binaries, Browsers
validations:
required:true
- type:dropdown
id:package-manager
attributes:
label:Used Package Manager
description:Select the used package manager
options:
- npm
- yarn
- pnpm
- bun
validations:
required:true
- type:checkboxes
id:checkboxes
attributes:
label:Validations
description:Before submitting the issue, please make sure you do the following
options:
- label:Read the [Contributing Guidelines](https://github.com/wxt-dev/wxt/blob/main/CONTRIBUTING.md).
required:true
- label:Read the [docs](https://wxt.dev/guide/installation.html).
required:true
- label:Check that there isn't [already an issue](https://github.com/wxt-dev/wxt/issues) that reports the same bug to avoid creating a duplicate.
required:true
- label:Check that this is a concrete bug. For Q&A open a [GitHub Discussion](https://github.com/wxt-dev/wxt/discussions) or join our [Discord Chat Server](https://discord.gg/ZFsZqGery9).
required:true
- label:The provided reproduction is a [minimal reproducible example](https://stackoverflow.com/help/minimal-reproducible-example) of the bug.
- Upgrade vite (`v4.3` → `v4.4`) ([547c185](https://github.com/wxt-dev/wxt/commit/547c185))
- Update templates to work with CSS entrypoints ([7f15305](https://github.com/wxt-dev/wxt/commit/7f15305))
- Improve file list output in CI ([#73](https://github.com/wxt-dev/wxt/pull/73))
### 🤖 CI
- Validate templates against `main` ([#66](https://github.com/wxt-dev/wxt/pull/66))
- List vite version when validating project templates ([ef140dc](https://github.com/wxt-dev/wxt/commit/ef140dc))
- Validate templates using tarball to avoid version conflicts within the `wxt/node_modules` directory ([edfa075](https://github.com/wxt-dev/wxt/commit/edfa075))
If you are changing the docs or fixing a bug, feel free to fork and open a PR.
@@ -8,9 +8,17 @@ If you want to add a new feature, please create an issue or discussion first so
## Conventional Commits
This project uses [Conventional Commits](https://www.conventionalcommits.org/en) to automate versioning. If you're a new contributor, don't worry about this. When you open a PR, a maintainer will change the PR's title so it's in the style of conventional commits, but that's all.
This project uses [Conventional Commit format](https://www.conventionalcommits.org/en/v1.0.0/) to automatically generate a changelog and better understand the changes in the project
Maintainers, commits to the `main` branch (either directly or via PRs) must be valid conventional commits.
Here are some examples of conventional commit messages:
-`feat: add new functionality`
-`fix: correct typos in code`
-`ci: add GitHub Actions for automated testing`
## Conventional PR Titles
The title of your pull request should follow the [conventional commit format](#conventional-commits). When a pull request is merged to the main branch, all changes are going to be squashed into a single commit. The message of this commit will be the title of the pull request. And for every release, the commit messages are used to generate the changelog.
## Setup
@@ -32,18 +40,19 @@ Here are some helpful commands:
```sh
# Build WXT package
cd packages/wxt
pnpm build
```
```sh
# Build WXT package, then build demo extension
cd demo
cdpackages/wxt-demo
pnpm build
```
```sh
# Build WXT package, then start the demo extension in dev mode
cd demo
cdpackages/wxt-demo
pnpm dev
```
@@ -57,9 +66,32 @@ pnpm test
pnpm docs:dev
```
## Profiling
```sh
# Build the latest version
pnpm --filter wxt build
# CD to the demo directory
cd packages/wxt-demo
# 1. Generate a flamechart with 0x
pnpm dlx 0x node_modules/wxt/bin/wxt.mjs build
# 2. Inspect the process with chrome @ chrome://inspect
Documentation is written with VitePress, and is located in the `docs/` directory.
The API reference is generated from JSDoc comments in the source code. If there's a typo or change you want to make in there, you'll need to update the source code instead of a file in the `docs/` directory.
## Testing
WXT has unit and E2E tests. When making a change or adding a feature, make sure to update the tests or add new ones.
WXT has unit and E2E tests. When making a change or adding a feature, make sure to update the tests or add new ones, if they exist.
> If they don't exist, feel free to create them, but that's a lot for a one-time contributor. A maintainer might add them to your PR though.
To run tests for a specific file, add the filename at the end of the test command:
@@ -67,6 +99,88 @@ To run tests for a specific file, add the filename at the end of the test comman
pnpm test manifest-contents
```
Unit and E2E tests are ran together via [Vitest workspaces](https://vitest.dev/guide/#workspaces-support).
All test (unit and E2E) for all packages are ran together via [Vitest workspaces](https://vitest.dev/guide/#workspaces-support).
If you want to manually test a change, you can modify the demo project for your test, but please don't leave those changes committed once you open a PR.
## Templates
Each directory inside `templates/` is it's own standalone project. Simply `cd` into the directory you're updating, install dependencies with `npm` (NOT `pnpm`), and run the relevant commands
```sh
cd templates/vue
npm i
npm run dev
npm run build
```
Note that templates are hardcoded to a specific version of `wxt` from NPM, they do not use the local version. PR checks will test your PR's changes against the templates, but if you want to manually do it, update the package.json dependency:
```diff
"devDependencies": {
"typescript": "^5.3.2",
"vite-plugin-solid": "^2.7.0",
- "wxt": "^0.8.0"
+ "wxt": "../.."
}
```
Then run `npm i` again.
### Adding Templates
To add a template, copy the vanilla template and give it a new name.
That's it. Once your template is merged, it will be available inside `wxt init` immediately. You don't need to release a new version of WXT to release a new template.
## Releasing Updates
Releases are done with GitHub actions:
- Use the [Release workflow](https://github.com/wxt-dev/wxt/actions/workflows/release.yml) to release a single package in the monorepo. This automatically detects the version change with conventional commits, builds and uploads the package to NPM, and creates a GitHub release.
- Use the [Sync Releases workflow](https://github.com/wxt-dev/wxt/actions/workflows/sync-releases.yml) to sync the GitHub releases with changes to the changelog. To change a release, update the `CHANGELOG.md` file and run the workflow. It will sync the releases of a single package in the monorepo.
## Upgrading Dependencies
Use [`taze`](https://www.npmjs.com/package/taze) to upgrade dependencies throughout the entire monorepo.
```sh
pnpm dlx taze -r
```
Configuration is in [`taze.config.ts`](./taze.config.ts).
## Install Unreleased Versions
This repo uses https://pkg.pr.new to publish versions of all it's packages for almost every commit. You can install them via:
```sh
npm i https://pkg.pr.new/[package-name]@[ref]
```
Or use one of the shorthands:
```sh
# Install the latest build of `wxt` from a PR:
npm i https://pkg.pr.new/wxt@1283
# Install the latest build of `@wxt-dev/module-react` on the `main` branch
npm i https://pkg.pr.new/@wxt-dev/module-react@main
# Install `@wxt-dev/storage` from a specific commit:
npm i https://pkg.pr.new/@wxt-dev/module-react@426f907
```
## Blog Posts
Anyone is welcome to submit a blog post on https://wxt.dev/blog!
> [!NOTE]
> Before starting on a blog post, please message Aaron on Discord or start a discussion on GitHub to get permission to write about a topic, but most topics are welcome: Major version updates, tutorials, etc.
- **English only**: Blog posts should be written in English. Unfortunately, our maintainers doesn't have the bandwidth right now to translate our docs, let alone blog posts. Sorry 😓
- **AI**: Please only use AI to translate or proof-read your blog post. Don't generate the whole thing... We don't want to publish that.
Or see the [installation guide](https://wxt.dev/get-started/installation.html) to get started with WXT.
<!-- /automd -->
Or see the [installation guide](https://wxt.dev/guide/installation.html) to get started with WXT.
## Features
@@ -41,17 +68,28 @@ Or see the [installation guide](https://wxt.dev/get-started/installation.html) t
- 📂 File based entrypoints
- 🚔 TypeScript
- 🦾 Auto-imports
- ⬇️ Download and bundle remote URL imports
- 🎨 Frontend framework agnostic: works with Vue, React, Svelte, etc
- 🖍️ Quickly bootstrap a new project
### Coming Soon
- 📏 Bundle analysis
- 🤖 Automated publishing
- 🎨 Frontend framework agnostic: works with Vue, React, Svelte, etc
- 📦 [Module system](https://wxt.dev/guide/essentials/wxt-modules.html#overview) for reusing code between extensions
- 🖍️ Quickly bootstrap a new project
- 📏 Bundle analysis
- ⬇️ Download and bundle remote URL imports
## Sponsors
WXT is a [MIT-licensed](https://github.com/wxt-dev/wxt/blob/main/LICENSE) open source project with its ongoing development made possible entirely by the support of these awesome backers. If you'd like to join them, please consider [sponsoring WXT's development](https://github.com/sponsors/wxt-dev).
"WXT provides the best developer experience, making it quick, easy, and fun to develop web extensions. With built-in utilities for building, zipping, and publishing your extension, it's easy to get started.";
The extension messaging APIs are difficult to learn. Let's go beyond the simple examples from Chrome and Firefox's documentation to build our own simple messaging system from scratch.
description: Learn how WXT's new <code>#imports</code> module works and how to use it.
authors:
- name: Aaron Klinker
github: aklinker1
date: 2024-12-06T14:39:00.000Z
---
WXT v0.20 introduced a new way of manually importing its APIs: **the `#imports` module**. This module was introduced to simplify import statements and provide more visibility into all the APIs WXT provides.
The `#imports` module is considered a "virtual module", because the file doesn't actually exist. At build-time, imports are split into individual statements for each API:
:::code-group
```ts [What you write]
import { defineContentScript, injectScript } from '#imports';
```
```ts [What the bundler sees]
import { defineContentScript } from 'wxt/utils/define-content-script';
import { injectScript } from 'wxt/utils/inject-script';
```
:::
Think of `#imports` as a convenient way to access all of WXT's APIs from one place, without impacting performance or bundle size.
This enables better tree-shaking compared to v0.19 and below.
:::tip Need to lookup the full import path of an API?
Open up your project's `.wxt/types/imports-module.d.ts` file.
:::
## Mocking
When writing tests, you might need to mock APIs from the `#imports` module. While mocking these APIs is very easy, it may not be immediately clear how to accomplish it.
Let's look at an example using Vitest. When [configured with `wxt/testing`](/guide/essentials/unit-testing#vitest), Vitest sees the same transformed code as the bundler. That means to mock an API from `#imports`, you need to call `vi.mock` with the real import path, not `#imports`:
```ts
import { injectScript } from '#imports';
import { vi } from 'vitest';
vi.mock('wxt/utils/inject-script')
const injectScriptMock = vi.mocked(injectScript);
injectScriptMock.mockReturnValueOnce(...);
```
## Conclusion
You don't have to use `#imports` if you don't like - you can continue importing APIs from their submodules. However, using `#imports` is the recommended approach moving forwards.
- As more APIs are added, you won't have to memorize additional import paths.
- If breaking changes are made to import paths in future major versions, `#imports` won't break.
Happy Coding 😄
> P.S. Yes, this is exactly how [Nuxt's `#imports`](https://nuxt.com/docs/guide/concepts/auto-imports#explicit-imports) works! We use the exact same library, [`unimport`](https://github.com/unjs/unimport).
---
[Discuss this blog post on Github](https://github.com/wxt-dev/wxt/discussions/1543).
WXT has two directories for storing assets like CSS, images, or fonts.
-`<srcDir>/public`: Store files that will be copied into the output directory as-is
-`<srcDir>/assets`: Store files that will be processed by Vite during the build process
## `/public` Directory
Place static files like the extension icon or `_locales/` directory here. These files will be copied over to the output directory without being transformed by Vite.
```
<srcDir>
└─ public/
├─ icon-16.png
├─ icon-32.png
├─ icon-48.png
├─ icon-96.png
└─ icon-128.png
```
### Example
You can reference these files by using absolute paths in HTML files or `browser.runtime.getURL` in content scripts.
Files in the assets directory will be processed by Vite. They are imported in your source code, and will be transformed or renamed in the output directory.
You can build an extension for any combination of browser and manifest verison. Different browsers and manifest versions support different APIs and entrypoints, so be sure to check that your extension functions as expected for each target.
Separate build targets are written to their own output directories:
```
<rootDir>
└─ .output
├─ chrome-mv3
├─ firefox-mv2
├─ edge-mv3
└─ ...
```
## Target Browser
To build for a specific browser, pass the `-b --browser` flag from the CLI:
```
wxt --browser firefox
wxt build --browser firefox
```
By default, it will build for `chrome`. When excluding the [`--mv2` or `--mv3` flags](#target-manifest-version), it will default to the commonly accepted manifest version used with that browser.
| Browser | Default Manifest Version |
| ---------------- | :----------------------: |
| `chrome` | 3 |
| `firefox` | 2 |
| `safari` | 2 |
| `edge` | 3 |
| Any other string | 3 |
## Target Manifest Version
To build for a specific manifest version, pass either the `--mv2` flag or `--mv3` flag from the CLI.
```sh
wxt --mv2
wxt build --mv2
```
When the `-b --browser` flag is not passed, it defaults to `chrome`. So here, we're targetting MV2 for Chrome.
WXT's main goal is improving the development experience (DX) of creating web extensions. There are two things WXT does differently:
1. Automatically opens a browser with the extension installed when starting development
2. Reload each part of the extension individually rather than reloading the entire extension
Opening a browser automatically makes it super easy to start and stop development without having to manually load the extension in your browser.
Reloading each part of the extension individually improves your iteration speed while developing UIs. This is because reloading the entire extension on every change will close the popup and any tabs open to an extension page, like options. If you save a file associated with a UI and a content script while working on the UI, it will randomly close because it needed to reload the extension when the content script changed. This interupts your development flow and is really annoying.
WXT solves this problem by reloading HTML pages and content scripts individually (when possible) to keep your UIs open while you develop them. This is a MV3 feature, so if you're developing a MV2 extension, you'll get the same dev experience as Plasmo.
:::info
Unfortunately, there isn't an API for reloading the background page/service worker individually, so if you change a file used by the background, the entire extension will reload. See [Issue #53](https://github.com/wxt-dev/wxt/issues/53) for more details.
WXT's behavior can be configured via the `wxt.config.ts` file. In this file, you can add Vite plugins, change the directory strucutre of your project, and set fields on your `manifest.json`.
## Config File
To configure WXT, create a `wxt.config.ts` file in your project root. It should have the following contents:
```ts
import{defineConfig}from'wxt';
exportdefaultdefineConfig({
// My WXT config
});
```
:::info
See the [Config reference](/config.md) for a full list of options.
:::
## Directory Config
WXT allows you to edit several directories to your liking:
-`root` (default: `process.cwd()`) - Root of the WXT project
-`srcDir` (default: `<rootDir>`) - Location of all your source code
-`entrypointsDir` (default: `<srcDir>/entrypoints`) - Folder containing all the entrypoints.
But not all entrypoints are added to the `manifest.json`. If the filename is not recognized by WXT, they are still built and included in the extension, but they are considered "unlisted" and are not apart of the manifest.
In this case, `injected.ts` gets output to `<outdir>/injected.js` and is accessible via `browser.runtime.getURL("/injected.js")`.
:::info
See [`/entrypoints` folder](/guide/background.md) documentation for a full list of recognized entrypoint filenames.
:::
## Entrypoint Options
Some entrypoints, like content scripts, actions, or the background, can recieve additional options.
In HTML files, options are listed as `meta` tags:
```html
<html>
<head>
<!-- Defining the popup's "default_icon" field -->
Bootstrap a new project, start from scratch, or migrate an existing project.
:::warning 🚧 WSL Support
**_WXT does not support [Windows Subsystem for Linux](https://learn.microsoft.com/en-us/windows/wsl/) yet_**. See [Issue #55](https://github.com/wxt-dev/wxt/issues/55) to track progress.
"zip:firefox": "wxt zip --browser firefox", // [!code ++]
"postinstall": "wxt prepare" // [!code ++]
}
}
```
## Migrate an Existing Project
Before starting the migration, it is recommended to run `pnpx wxt@latest init` to see what a basic project looks like. Once you have an understanding of how WXT projects are structured, you're ready to convert the project, using the initialized project as a reference.
Migrating a project to WXT comes down to a few steps:
1. Install WXT and remove any old build tools: `pnpm i -D wxt`
1. Refactoring/move your entrypoints to the `entrypoints` directory
1. Moving public assets to the `public` directory
1. Update the dev and build scripts to use WXT
1. Ensure project is compatible with Vite, which is used under the hood to bundle your extension
:::info
Since projects vary greatly in setup, [start a discussion on GitHub](https://github.com/wxt-dev/wxt/discussions/new/choose) if you need help migrating your project to WXT.
:::
## Development
Once you've installed WXT, you can start the development server using the `dev` script.
```sh
pnpm dev
```
:::tip 🎉 Well done!
The dev command will build the extension for development, open the browser, and reload the different parts of the extension when you save changes.
:::
:::details Development Manifest
When running the dev command, WXT will make several changes to your `manifest.json` to improve your development experience:
- If missing, add a background script/service worker to enable fast reloads
- Add serveral `permissions` and `host_permissions` to enable HMR and fast reloads
- Modify the CSP to allow connections with the dev server
- Remove `content_scripts` and register them at runtime so they can be easily reloaded when you save a file
If you're an experienced web extension developer and think the dev manifest looks wrong, this is why. Run a production build with `wxt build` to see the unmodified `manifest.json`.
:::
## Next Steps
You're ready to build your web extension!
- Learn how to [add entrypoints](./entrypoints.md) like the popup, options page, or content scripts
- [Configure WXT](./configuration.md) by creating a `wxt.config.ts` file
- Checkout [example projects](https://github.com/wxt-dev/wxt-examples) to see how to perfom common tasks with WXT
WXT is a free and open source framework for building web extensions in an conventional, intuative, and safe way **_for all browsers_**.
WXT is based of [Nuxt](https://nuxt.com), and aims to provide the same great DX with TypeScript, auto-imports, and an opinionated project structure.

## Conventions
WXT is an optionated framework. This helps keep projects consistent and easy to pick up.
- **Generated manifest**: Based on your project's file structure
- **Entrypoint configuration**: Configure entrypoints from the same file they're declare in
- **Type-safety is a priority**: Out-of-the-box TypeScript support with improved browser API typing
- **Simple output file structure**: Ouptut file paths minimize the path at runtime
## Development
WXT's dev server supports modern features like HMR to provide a lighting fast dev mode.
When changes can't be hot-reloaded, like content scripts or background scripts, they're reloaded individually to prevent reloading the entire extension and slowing down your development cycle.
## Production-ready
Production builds are optimized for store review, changing as few files as possible between builds.
In addition, WXT fully supports Firefox's source code requirements when using a bundler. It will automatically create and upload a ZIP file of your source code.
:::info
See [Publishing](./publishing.md) for more info around production builds.
WXT offers several utilities that simplify the publishing process.
## First Time Publishing
If you're publishing an extension to a store for the first time, it's recommended that you manually navigate the process. Each store has unique steps and requirements that you need to familiarize yourself with.
Each store requires that a ZIP file be uploaded. You can generate these using the `wxt zip` command:
```sh
wxt zip
wxt zip -b firefox
# etc
```
Generated ZIP files are stored in the `.output` directory.
## Automation
To automate releasing updates, use the [`publish-browser-extension`](https://www.npmjs.com/package/publish-browser-extension) package.
:::info
🚧 WXT plans to eventually incorporate the `publish-browser-extension` package into its own `wxt submit` command.
Here's an example of a GitHub Action to automate submiting new versions of your extension for review. Ensure that you've added all required secrets used in the workflow to the repo's settings.
Firefox requires you to upload a ZIP of your source code. This allows them to rebuild your extension and review the code in a readable way. More details can be found in [Firefox's docs](https://extensionworkshop.com/documentation/publish/source-code-submission/).
WXT and `publish-browser-extension` both fully support generating and automatically submitting a source code ZIP.
When you run `wxt zip -b firefox`, your sources are zipped into the `.output` directory along with your built extension. WXT is configured to exclude certain files such as config files, hidden files, and tests. However, it's important to manually check the ZIP to ensure it only contains the files necessary to rebuild your extension.
To customize which files are zipped, add the `zip` option to your config file.
```ts
// wxt.config.ts
import { defineConfig } from 'wxt';
export default defineConfig({
zip: {
// ...
},
});
```
If it's your first time submitting to the Firefox Addon Store, or if you've updated your project layout, always test your sources ZIP! The commands below should allow you to rebuild your extension from inside the extracted ZIP.
:::code-group
```sh [pnpm]
pnpm i
pnpm zip:firefox
```
```sh [npm]
npm i
npm run zip:firefox
```
```sh [yarn]
yarn
yarn zip:firefox
```
:::
Ensure that you have a `README.md` or `SOURCE_CODE_REVIEW.md` file with the above commands so that the Firefox team knows how to build your extension.
## Safari
🚧 Not automated at this time
:::warning
🚧 WXT does not currently support automated publishing for Safari. Safari extensions require a native MacOS or iOS app wrapper, which WXT cannot create at this time. For now, if you want to publish to Safari, follow this guide:
For MV2, the background is added as a script to the background page. For MV3, the background becomes a service worker.
## Filenames
<EntrypointPatterns
:patterns="[
['background.ts', 'background.js'],
['background/index.ts', 'background.js'],
]"
/>
## Definition
:::warning
The main function of the background **_CANNOT BE ASYNC_**. Event listeners must be added syncronously on background startup. If your main function returns a promise, WXT will log an error.
:::
```ts
exportdefaultdefineBackground(()=>{
// Executed when background is loaded
});
```
or
```ts
exportdefaultdefineBackground({
// Set manifest options
persistent: undefined|true|false,
type:undefined|'module',
// Set include/exclude if the background should be removed from some builds
// Set include/exclude if the background should be removed from some builds
include: undefined|string[],
exclude: undefined|string[],
main(ctx){
// Executed when content script is loaded
},
});
```
> All manifest options default to `undefined`.
When defining multiple content scripts, content script entrypoints that have the same set of options will be merged into a single `content_script` item in the manifest.
## CSS
To include CSS with your content script, import the CSS file at the top of your entrypoint.
Old content scripts are not automatically stopped when an extension updates and restarts. Often, this leads to "Invalidated context" errors in production when a content script from an old version of your extension tries to use a web extension API. Since it's not connected to the latest version of your extension, the browser decides to throw an error.
WXT provides a utility for managing this process: `ContentScriptContext`. An instance of this class is provided to you automatically inside the `main` function of your content script.
```ts
exportdefaultdefineContentScript({
// ...
main(ctx: ContentScriptContext){
// Add custom listeners for stopping work
ctx.onInvalidated(()=>{
// ...
});
// Stop fetch requests
fetch('...url',{signal: ctx.signal});
// Timeout utilities
ctx.setTimeout(()=>{
// ...
},5e3);
ctx.setInterval(()=>{
// ...
},60e3);
},
});
```
The class extends [`AbortController`](https://developer.mozilla.org/en-US/docs/Web/API/AbortController) and provides other utilities for stopping a content script's logic once it becomes invalidated.
:::tip
When working with content scripts, **you should always use the `ctx` object to stop any async or future work.**
This prevents old content scripts from interfering with new content scripts, and prevents error messages from the console in production.
WXT can build CSS entrypoints individually. CSS entrypoints are always unlisted.
See [Content Script CSS](/guide/content-scripts.md#css) documentation for the recomended approach to include CSS with a content script.
:::info
If the recommended approach doesn't work for your use case, you can use any of the filename patterns below to build the styles separate from the JS and use the [`transformManifest` hook](/config.md#transformmanifest) to manually add your CSS file to the manifest.
Any assets imported or referenced inside the `<srcDir>/assets/` directory will be processed by WXT's bundler.
Here's how you access them:
:::code-group
```ts [JS]
import imageUrl from '~/assets/image.png';
const img = document.createElement('img');
img.src = imageUrl;
```
```html [HTML]
<!-- In HTML tags, you must use the relative path --->
<img src="../assets/image.png" />
```
```css [CSS]
.bg-image {
background-image: url(~/assets/image.png);
}
```
```vue [Vue]
<script>
import image from '~/assets/image.png';
</script>
<template>
<img :src="image" />
</template>
```
```jsx [JSX]
import image from '~/assets/image.png';
<img src={image} />;
```
:::
## `/public` Directory
Files inside `<rootDir>/public/` are copied into the output folder as-is, without being processed by WXT's bundler.
Here's how you access them:
:::code-group
```ts [JS]
import imageUrl from '/image.png';
const img = document.createElement('img');
img.src = imageUrl;
```
```html [HTML]
<img src="/image.png" />
```
```css [CSS]
.bg-image {
background-image: url(/image.png);
}
```
```vue [Vue]
<template>
<img src="/image.png" />
</template>
```
```jsx [JSX]
<img src="/image.png" />
```
:::
:::warning
Assets in the `public/` directory are **_not_** accessible in content scripts by default. To use a public asset in a content script, you must add it to your manifest's [`web_accessible_resources` array](/api/reference/wxt/type-aliases/UserManifest#web-accessible-resources).
:::
## Inside Content Scripts
Assets inside content scripts are a little different. By default, when you import an asset, it returns just the path to the asset. This is because Vite assumes you're loading assets from the same hostname.
But, inside content scripts, the hostname is whatever the tab is set to. So if you try to fetch the asset, manually or as an `<img>`'s `src`, it will be loaded from the tab's website, not your extension.
To fix this, you need to convert the image to a full URL using `browser.runtime.getURL`:
How a `.wasm` file is loaded varies greatly between packages, but most follow a basic setup: Use a JS API to load and execute the `.wasm` file.
For an extension, that means two things:
1. The `.wasm` file needs to be present in output folder so it can be loaded.
2. You must import the JS API to load and initialize the `.wasm` file, usually provided by the NPM package.
For an example, let's say you have a content script needs to parse TS code into AST. We'll use [`@oxc-parser/wasm`](https://www.npmjs.com/package/@oxc-parser/wasm) to do it!
First, we need to copy the `.wasm` file to the output directory. We'll do it with a [WXT module](/guide/essentials/wxt-modules):
Run `wxt build`, and you should see the WASM file copied into your `.output/chrome-mv3` folder!
Next, since this is in a content script and we'll be fetching the WASM file over the network to load it, we need to add the file to the `web_accessible_resources`:
```ts [wxt.config.ts]
export default defineConfig({
manifest: {
web_accessible_resources: [
{
// We'll use this matches in the content script as well
matches: ['*://*.github.com/*'],
// Use the same path as `relativeDest` from the WXT module
resources: ['/oxc_parser_wasm_bg.wasm'],
},
],
},
});
```
And finally, we need to load and initialize the `.wasm` file inside the content script to use it:
```ts [entrypoints/content.ts]
import initWasm, { parseSync } from '@oxc-parser/wasm';
This code is taken directly from `@oxc-parser/wasm` docs with one exception: We manually pass in a file path. In a standard NodeJS or web project, the default path works just fine so you don't have to pass anything in. However, extensions are different. You should always explicitly pass in the full URL to the WASM file in your output directory, which is what `browser.runtime.getURL` returns.
Run your extension, and you should see OXC parse the TS file!
WXT uses [`unimport`](https://www.npmjs.com/package/unimport), the same tool as Nuxt, to setup auto-imports.
```ts
exportdefaultdefineConfig({
// See https://www.npmjs.com/package/unimport#configurations
imports:{
// ...
},
});
```
By default, WXT automatically sets up auto-imports for all of it's own APIs and some of your project directories:
-`<srcDir>/components/*`
-`<srcDir>/composables/*`
-`<srcDir>/hooks/*`
-`<srcDir>/utils/*`
All named and default exports from files in these directories are available everywhere else in your project without having to import them.
To see the complete list of auto-imported APIs, run [`wxt prepare`](/api/cli/wxt-prepare) and look at your project's `.wxt/types/imports-module.d.ts` file.
## TypeScript
For TypeScript and your editor to recognize auto-imported variables, you need to run the [`wxt prepare` command](/api/cli/wxt-prepare).
Add this command to your `postinstall` script so your editor has everything it needs to report type errors after installing dependencies:
```jsonc
// package.json
{
"scripts":{
"postinstall":"wxt prepare",// [!code ++]
},
}
```
## ESLint
ESLint doesn't know about the auto-imported variables unless they are explicitly defined in the ESLint's `globals`. By default, WXT will generate the config if it detects ESLint is installed in your project. If the config isn't generated automatically, you can manually tell WXT to generate it.
:::code-group
```ts [ESLint 9]
export default defineConfig({
imports: {
eslintrc: {
enabled: 9,
},
},
});
```
```ts [ESLint 8]
export default defineConfig({
imports: {
eslintrc: {
enabled: 8,
},
},
});
```
:::
Then in your ESLint config, import and use the generated file:
:::code-group
```js [ESLint 9]
// eslint.config.mjs
import autoImports from './.wxt/eslint-auto-imports.mjs';
export default [
autoImports,
{
// The rest of your config...
},
];
```
```js [ESLint 8]
// .eslintrc.mjs
export default {
extends: ['./.wxt/eslintrc-auto-import.json'],
// The rest of your config...
};
```
:::
## Disabling Auto-imports
Not all developers like auto-imports. To disable them, set `imports` to `false`.
```ts
export default defineConfig({
imports: false, // [!code ++]
});
```
## Explicit Imports (`#imports`)
You can manually import all of WXT's APIs via the `#imports` module:
```ts
import {
createShadowRootUi,
ContentScriptContext,
MatchPattern,
} from '#imports';
```
To learn more about how the `#imports` module works, read the [related blog post](/blog/2024-12-06-using-imports-module).
If you've disabled auto-imports, you should still use `#imports` to import all of WXT's APIs from a single place.
> See the [API Reference](/api/reference/wxt/interfaces/WebExtConfig) for a full list of config.
During development, WXT uses [`web-ext` by Mozilla](https://www.npmjs.com/package/web-ext) to automatically open a browser window with your extension installed.
## Config Files
You can configure browser startup in 3 places:
1.`<rootDir>/web-ext.config.ts`: Ignored from version control, this file lets you configure your own options for a specific project without affecting other developers
```ts [web-ext.config.ts]
import { defineWebExtConfig } from 'wxt';
export default defineWebExtConfig({
// ...
});
```
2. `<rootDir>/wxt.config.ts`: Via the [`webExt` config](/api/reference/wxt/interfaces/InlineConfig#webext), included in version control
3. `$HOME/web-ext.config.ts`: Provide default values for all WXT projects on your computer
## Recipes
### Set Browser Binaries
To set or customize the browser opened during development:
```ts [web-ext.config.ts]
export default defineWebExtConfig({
binaries: {
chrome: '/path/to/chrome-beta', // Use Chrome Beta instead of regular Chrome
firefox: 'firefoxdeveloperedition', // Use Firefox Developer Edition instead of regular Firefox
edge: '/path/to/edge', // Open MS Edge when running "wxt -b edge"
},
});
```
By default, WXT will try to automatically discover where Chrome/Firefox are installed. However, if you have chrome installed in a non-standard location, you need to set it manually as shown above.
### Persist Data
By default, to keep from modifying your browser's existing profiles, `web-ext` creates a brand new profile every time you run the `dev` script.
Right now, Chromium based browsers are the only browsers that support overriding this behavior and persisting data when running the `dev` script multiple times.
Now, next time you run the `dev` script, a persistent profile will be created in `.wxt/chrome-data/{profile-name}`. With a persistent profile, you can install devtools extensions to help with development, allow the browser to remember logins, etc, without worrying about the profile being reset the next time you run the `dev` script.
:::tip
You can use any directory you'd like for `--user-data-dir`, the examples above create a persistent profile for each WXT project. To create a profile for all WXT projects, you can put the `chrome-data` directory inside your user's home directory.
:::
### Disable Opening Browser
If you prefer to load the extension into your browser manually, you can disable the auto-open behavior:
To generate the manifest and other files at build-time, WXT must import each entrypoint to get their options, like content script `matches`. For HTML files, this is easy. For JS/TS entrypoints, the process is more complicated.
When loading your JS/TS entrypoints, they are imported into a NodeJS environment, not the `browser` environment that they normally run in. This can lead to issues commonly seen when running browser-only code in a NodeJS environment, like missing global variables.
WXT does several pre-processing steps to try and prevent errors during this process:
1. Use `linkedom` to make a small set of browser globals (`window`, `document`, etc) available.
2. Use `@webext-core/fake-browser` to create a fake version of the `chrome` and `browser` globals expected by extensions.
3. Pre-process the JS/TS code, stripping out the `main` function then tree-shaking unused code from the file
However, this process is not perfect. It doesn't setup all the globals found in the browser and the APIs may behave differently. As such, **_you should avoid using browser or extension APIs outside the `main` function of your entrypoints!_**
:::tip
If you're running into errors while importing entrypoints, run `wxt prepare --debug` to see more details about this process. When debugging, WXT will print out the pre-processed code to help you identify issues.
:::
Once the environment has been polyfilled and your code pre-processed, it's up the entrypoint loader to import your code, extracting the options from the default export.
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