BREAKING CHANGE: Updates `.wxt/tsconfig.json` defaults to latest recommended settings for vite projects and requires Typescript 5.4 or later. See #2512 for details on what compiler options were changed.
Co-authored-by: cookesan <cookesan@users.noreply.github.com>
BREAKING CHANGE: If your script needs to return a value, like for `browser.scripting.executeScript`, set `globalName: true` to maintain the old behavior.
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`.
If you are changing the docs or fixing a bug, feel free to fork and open a PR.
If you want to add a new feature, please create an issue or discussion first so we can decide if the feature is inline with the vision for WXT.
## WXT's Vision
WXT is two things:
1. A build tool
2. A set of runtime utilities
The long term goal of WXT is provide an opinionated build tool that keeps WXT projects standard, while providing light-weight runtime utils that simplify a lot of the boilerplate/overhead when setting up a new extension.
I also want to provide a way for developers to use either one of those two things independently, and not require them to use both. This is why all of WXT's runtime utils are shipped as their own NPM packages, most of them not bundled inside the core `wxt` package. If you just want to use the packages, they're available, and if you just want to use WXT's built tool, you don't have to import any of WXT's utilities, you can use your own.
> The few runtime utils shipped inside WXT are things that should be used by 90% of extensions. That said, they're also legacy utils left in from before I started creating separate NPM packages, and in the future, they may be removed from the core package.
## 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.
## Breaking Changes Policy
A quick word on WXT's breaking changes policy. I am willing to make breaking changes, but they have to be for a good enough reason - they have to make WXT better as a whole, they can't be based on one opinion.
Breaking changes also require a major release. Major releases have happened once or twice a year, so after you merge your PR, you'll have to wait a little bit before it is released.
To make a breaking change:
1. Make sure you're PR is targeting the `major` branch
2. Add `!` after the conventional commit type (`fix!: ...`, `feat!: ...`, `chore!: ...`, etc) to indicate that it is a breaking change
3. At the top of the PR, provide documentation that will inform developers about the breaking change, why it was done, and how to migrate their extension so nothing breaks.
- This documentation will be put ["Upgrading WXT"](https://wxt.dev/guide/resources/upgrading.html) page in the docs, read through previous breaking change docs for an idea of what is required.
## Setup
WXT uses `pnpm`, so make sure you have it installed.
WXT uses Bun for package management and development. Install it from: <https://bun.com/>
Then install dependencies:
```sh
corepack enable
```
Then, simply run the install command:
```sh
pnpm i
bun install
```
## Development
@@ -31,32 +61,68 @@ pnpm i
Here are some helpful commands:
```sh
# Build WXT package
pnpm build
# Build WXT package and workspace dependencies
bun run --filter wxt build
```
```sh
# Build WXT package, then build demo extension
cd packages/wxt-demo
pnpm build
```
```sh
# Build WXT package, then start the demo extension in dev mode
cd packages/wxt-demo
pnpm dev
# Build workspace dependencies, then start the demo extension in dev mode
bun run --filter wxt-demo dev
```
```sh
# Run unit and E2E tests
pnpmtest
bun runtest
```
```sh
# Start the docs website locally
pnpm docs:dev
bun run docs:dev
```
> Above, we used bun's `--filter` flag to choose which package to run a command in, but there are other ways:
>
> ```sh
> bun run -F @wxt-dev/i18n build
> # or
> bun run --cwd packages/i18n build
> # or
> cd packages/i18n
> bun run build
> ```
>
> Pick your poison!
## Profiling
```sh
# Build the latest version
bun run --filter wxt build
# CD to the demo directory
cd packages/wxt-demo
```
Then there are a few different ways to profile WXT commands:
- Generate a flamechart with 0x:
```sh
bunx 0x node_modules/wxt/bin/wxt.mjs build
```
- Create a CPU profile:
```sh
bun run --cpu-prof node_modules/wxt/bin/wxt.mjs build
```
- Debug the process:
```sh
bun run --inspect node_modules/wxt/bin/wxt.mjs build
```
## Updating Docs
Documentation is written with VitePress, and is located in the `docs/` directory.
@@ -72,7 +138,7 @@ WXT has unit and E2E tests. When making a change or adding a feature, make sure
To run tests for a specific file, add the filename at the end of the test command:
```sh
pnpm test manifest-contents
bun run --filter wxt test manifest-contents
```
All test (unit and E2E) for all packages are ran together via [Vitest workspaces](https://vitest.dev/guide/#workspaces-support).
@@ -81,7 +147,7 @@ If you want to manually test a change, you can modify the demo project for your
## 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
Each directory inside `templates/` is it's own standalone project. Simply `cd` into the directory you're updating, install dependencies with `npm` (NOT `bun`), and run the relevant commands
```sh
cd templates/vue
@@ -97,7 +163,7 @@ Note that templates are hardcoded to a specific version of `wxt` from NPM, they
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
WXT has custom rules around what dependencies can be upgraded. Use the `scripts/upgrade-deps.ts` script to upgrade dependencies and follow these rules.
```sh
bun run scripts/upgrade-deps.ts
```
To see all the options, run:
```sh
bun run scripts/upgrade-deps.ts --help
```
## 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 don'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.
## Become a Maintainer
If you're interested in becoming a maintainer, send an email to Aaron at <aaronklinker1@gmail.com> with your github username saying you're interested. The process is very informal, I will add you quickly if you've contributed code or answered questions and helped out the community!
Maintainers don't have to just write code - they can manage issues, answer questions, review PRs, organize and prioritize work - there's lots of ways for you to help out.
A couple of things for you to consider before merging a PR or giving the go-ahead on a feature proposal.
## Be picky about new features and packages
We are responsible for maintaining them and fixing related bugs after the PR is merged. The community can always release their own WXT modules or packages, not everything needs to be built into WXT.
## Prefer standards over customization
Don't merge PRs that just add another way to do something, like [this one](https://github.com/wxt-dev/wxt/pull/2053#issuecomment-3857010196).
WXT is opinionated, if you have questions about what is WXT's opinion or we need to create a new one, create an issue and @ me to discuss.
## PRs should be small and targeted
A PR should make one change. They should not make any unrelated changes outside of accomplishing the one thing. This makes PRs easier to review and they get merged more quickly - a win-win for everyone.
## `@wxt-dev/*` packages are separate
We can't make changes to these packages assuming people are using them only with WXT. For example, I almost missed [this PR](https://github.com/wxt-dev/wxt/pull/2049#issuecomment-3861251599).
I want these packages to be usable on their own so if people don't like WXT's build tool, they can still use our other awesome packages.
## Minimize dependencies
I don't like how heavy lots of frameworks are. It's unavoidable to a certain extent, but if you can do something without another dependency, try to.
If you need a dependency, look for one with zero dependencies and that's respectable.
## Look at milestones
I've organized WXT's long term plans into [milestones](https://github.com/wxt-dev/wxt/milestones), check those out to get an idea of my priorities for some of the larger features.
## Require tests
If someone opens a PR to fix a bug but doesn't include tests, don't merge the PR. Tests are required to prevent regressions and maintain a codebase long term.
## Ask for reproductions for bugs
You don't need to triage bugs if someone doesn't give you enough information. You can always ask for a repo with a reproduction or wait for more details.
If there's not an easy way to reproduce a bug, you're wasting your time triaging it. Just be mindful of your own time!
Here's an example of how to ask for a reproduction: <https://github.com/wxt-dev/wxt/issues/2064#issuecomment-3862579110>. You could be more blunt than this.
## Add yourself as a code owner
If you want to be responsible for a specific package or directory, add yourself to the [`.github/CODEOWNERS`](https://github.com/wxt-dev/wxt/blob/main/.github/CODEOWNERS) file to get added as a reviewer to PRs automatically. You can also add yourself to the default list to be added as a reviewer on all PRs.
## Releasing Package 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.
## Creating New Packages
Example PR: <https://github.com/wxt-dev/wxt/pull/2152>
1. Create the package.
2. Update CI workflow inputs.
3. Add docs page and version for "Other Packages" dropdown.
4. Merge the PR.
5. Tag the commit (look at other tags for pattern):
```sh
git tag <dir-name>-v<version>
git push --tags
```
6. Publish the package to NPM:
```sh
cd packages/<dir-name>
bun publish --access public
```
7. Create a basic release on GitHub mentioning the new package is available.
A couple of things to note:
- pkg.pr.new will fail on the original PR. It's fine to ignore and merge your PR as long as it fails due to your new package not being published to NPM yet.
- The regular release workflow DOES NOT WORK for new packages. You have to have at least one `<dir-name>-v<version>` tag created before you can run that workflow for your new package.
- You don't need to create a CHANGELOG.md file for the package, it will be created automatically after future changes are released via the normal release workflow.
Or see the [installation guide](https://wxt.dev/guide/installation.html) to get started with WXT.
@@ -59,12 +50,19 @@ Or see the [installation guide](https://wxt.dev/guide/installation.html) to get
- 🦾 Auto-imports
- 🤖 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).
If you discover a security vulnerability, please email me at <aaronklinker1@gmail.com>. I will respond within a few days to acknowledge receipt of your report.
If the vulnerability is accepted, I will open a public issue to track the fix. If the vulnerability is not accepted, no further action will be taken.
"WXT provides the best developer experience, making it quick, easy, and fun to develop chrome extensions for all browsers. With built-in utilities for building, zipping, and publishing your extension, it's easy to get started.";
"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).
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.[jt]s', 'background.js'],
['background/index.[jt]s', 'background.js'],
]"
/>
## Definition
:::warning
The main function of the background **_CANNOT BE ASYNC_**. Event listeners must be added synchronously 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
// Configure how/when content script will be registered
registration: undefined|"manifest"|"runtime",
main(ctx: ContentScriptContext){
// 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.
WXT can build CSS entrypoints individually. CSS entrypoints are always unlisted.
See [Content Script CSS](/entrypoints/content-scripts#css) documentation for the recommended 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](/api/wxt/interfaces/InlineConfig#transformmanifest) to manually add your CSS file to the manifest.
Chrome extensions allow you to add panels and side panes to the devtools window.

See the WXT's examples for a full walkthrough of extending the devtools window:
HTML pages that are bundled and shipped with the extension, but are not included in the manifest.
If you plan on using the page in an iframe, don't forget to add the page to [`web_accessible_resources`](https://developer.chrome.com/docs/extensions/reference/manifest/web-accessible-resources).
TypeScript files that are bundled and shipped with the extension, but are not included in the manifest.
You are responsible for loading/running these scripts where needed. If necessary, don't forget to add the script and/or any related stylesheets to [`web_accessible_resources`](https://developer.chrome.com/docs/extensions/reference/manifest/web-accessible-resources).
## Filenames
<EntrypointPatterns
:patterns="[
['<name>.[jt]sx?', '<name>.js'],
['<name>/index.[jt]sx?', '<name>.js'],
]"
/>
## Definition
```ts
exportdefaultdefineUnlistedScript(()=>{
// Executed when script is loaded
});
```
or
```ts
exportdefaultdefineUnlistedScript({
// Set include/exclude if the script should be removed from some builds
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.
Lets compare the features of WXT vs [Plasmo](https://docs.plasmo.com/framework) (another web extension framework) and [CRXJS](https://crxjs.dev/vite-plugin) (the most popular bundler plugin).
WXT's main goal is improving the development experience (DX) of creating web extensions, while not sacrificing support. 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 interrupts 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 structure 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](/api/wxt/interfaces/InlineConfig) 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.
You want a `src/` directory to contain all your source code, and you want to rename `entrypoints/` → `entries/`:
```
<rootDir>
├─ src/
│ └─ entries/
│ ├─ background.ts
│ └─ ...
└─ wxt.config.ts
```
Your config would look like this:
```ts
import{defineConfig}from'wxt';
exportdefaultdefineConfig({
srcDir:'src',
entrypointsDir:'entries',
});
```
## Frontend Frameworks
Adding a framework like Vue, React, or Svelte is easy!
In the `wxt.config.ts` file, install and add the framework's Vite plugin to the config.
:::code-group
```ts [Vue]
import { defineConfig } from 'wxt';
import vue from '@vitejs/plugin-vue';
export default defineConfig({
vite: () => ({
plugins: [vue()],
}),
});
```
```ts [React]
import { defineConfig } from 'wxt';
import react from '@vitejs/plugin-react';
export default defineConfig({
vite: () => ({
plugins: [react()],
}),
});
```
```ts [Svelte]
import { defineConfig } from 'wxt';
import { svelte } from '@sveltejs/vite-plugin-svelte';
export default defineConfig({
vite: () => ({
plugins: [svelte()],
}),
});
```
:::
:::info
Internally, WXT runs `vite build` multiple times during a single build. It can't share the same instance of some plugins between each build, so a function is used to return completely new instances of each plugin for each build.
See the [API Reference](/api/wxt/client/functions/createIntegratedUi) for the complete list of options.
You can control how CSS is injected for an integrated content script UI with the [`cssInjectionMode`](/api/wxt/interfaces/BaseContentScriptEntrypointOptions#cssinjectionmode) property. Usually, you'll want to leave it as `"manifest"`, the default, so the UI inherits its style from the website's CSS.
## Shadow Root
Often in web extensions, you don't want your content script's CSS affecting the page, or vise-versa. The [`ShadowRoot`](https://developer.mozilla.org/en-US/docs/Web/API/ShadowRoot) API is ideal for this.
WXT's [`createShadowRootUi`](/api/wxt/client/functions/createShadowRootUi) abstracts all the `ShadowRoot` setup away, making it easy to create UIs with isolated CSS. It also supports an optional `isolateEvents` parameter to further isolate user interactions.
To use `createShadowRootUi`, follow these steps:
1. Import your CSS file at the top of your content script
2. Set [`cssInjectionMode: "ui"`](/api/wxt/interfaces/BaseContentScriptEntrypointOptions#cssinjectionmode) inside `defineContentScript`
3. Define your UI with `createShadowRootUi()`
4. Mount the UI so it is visible to users
:::code-group
```ts [Vanilla]
// 1. Import the style
import './style.css';
export default defineContentScript({
matches: ['<all_urls>'],
// 2. Set cssInjectionMode
cssInjectionMode: 'ui',
async main(ctx) {
// 3. Define your UI
const ui = await createShadowRootUi(ctx, {
name: 'example-ui',
position: 'inline',
onMount(container) {
// Define how your UI will be mounted inside the container
const app = document.createElement('p');
app.textContent = 'Hello world!';
container.append(app);
},
});
// 4. Mount the UI
ui.mount();
},
});
```
```ts [Vue]
// 1. Import the style
import './style.css';
import { createApp } from 'vue';
import App from './App.vue';
export default defineContentScript({
matches: ['<all_urls>'],
// 2. Set cssInjectionMode
cssInjectionMode: 'ui',
async main(ctx) {
// 3. Define your UI
const ui = await createShadowRootUi(ctx, {
name: 'example-ui',
position: 'inline',
onMount: (container) => {
// Define how your UI will be mounted inside the container
const app = createApp(App);
app.mount(container);
return app;
},
onRemove: (app) => {
// Unmount the app when the UI is removed
app?.unmount();
},
});
// 4. Mount the UI
ui.mount();
},
});
```
```tsx [React]
// 1. Import the style
import './style.css';
import ReactDOM from 'react-dom/client';
import App from './App.tsx';
export default defineContentScript({
matches: ['<all_urls>'],
// 2. Set cssInjectionMode
cssInjectionMode: 'ui',
async main(ctx) {
// 3. Define your UI
const ui = await createShadowRootUi(ctx, {
name: 'example-ui',
position: 'inline',
onMount: (container) => {
// Container is a body, and React warns when creating a root on the body, so create a wrapper div
const app = document.createElement('div');
container.append(app);
// Create a root on the UI container and render a component
See the [API Reference](/api/wxt/client/functions/createShadowRootUi) for the complete list of options.
:::info TailwindCSS
`createShadowRootUi` supports TailwindCSS out of the box! When importing the styles, just import the main CSS file containing the `@tailwind` directives, and everything will just work :+1:.
:::
## IFrame
If you don't need to run your UI in the same frame as the content script, you can use an IFrame to host your UI instead. Since an IFrame just hosts an HTML page, **_HMR is supported_**.
WXT provides a helper function, [`createIframeUi`](/api/wxt/client/functions/createIframeUi), which simplifies setting up the IFrame.
1. Create an HTML page that will be loaded into your IFrame
WXT's main goal is providing the best DX it possibly can. When running your extension in dev mode, each part of your extension is reloaded separately when possible.
| manifest.json | | | | 🟡 See [#16](https://github.com/wxt-dev/wxt/issues/16) |
| `wxt.config.ts` | | | | 🟡 See [#10](https://github.com/wxt-dev/wxt/issues/10) |
| `web-ext.config.ts` | | | | 🟡 See [#10](https://github.com/wxt-dev/wxt/issues/10) |
## Dev Mode vs Production Builds
There are some notable differences between the development and production versions of an extension. During development:
1.**Content scripts are not listed in the `manifest.json`** when targeting MV3. Instead, the [`scripting`](https://developer.chrome.com/docs/extensions/reference/api/scripting) permission is used to register content scripts at runtime so they can be reloaded individually.
To get the list of content scripts during development, run the following in the background's console:
2. **The CSP is modified to allow loading scripts from the dev server**. Make sure you're using Chrome v110 or above for HMR to work.
3. If you don't include a background script/service worker, one will be created to perform various tasks in dev mode, mostly related to reloading different parts of the extension on change.
For production builds, none of the above modifications will be applied, and you're extension/manifest will only include what you have defined.
## Configure Browser Startup
WXT uses [`web-ext` by Mozilla](https://github.com/mozilla/web-ext) to automatically open a browser with the extension installed. You can configure the runner's behavior via the [`runner`](/api/wxt/interfaces/InlineConfig#runner) option, or in a separate gitignored file, `web-ext.config.ts`.
:::code-group
```ts [wxt.config.ts]
import { defineConfig } from 'wxt';
export default defineConfig({
runner: {
// Runner config
},
});
```
```ts [web-ext.config.ts]
import { defineRunnerConfig } from 'wxt';
export default defineRunnerConfig({
// Runner config
});
```
:::
### Browser Binaries
`web-ext`'s browser discovery is very limited. By default, it only guesses at where Chrome and Firefox are installed. If you've customized your install locations, you may need to tell `web-ext` where the binaries/executables are located using the [`binaries` option](/api/wxt/interfaces/ExtensionRunnerConfig#binaries). For other Chromium based browsers, like Edge or Opera, you'll need to explicitly list them in the `binaries` option as well, otherwise they will open in Chrome by default.
```ts
// ~/web-ext.config.ts
import { defineRunnerConfig } from 'wxt';
export default defineRunnerConfig({
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"
},
});
```
:::tip
When configuring browser binaries, it's helpful to put them in `~/web-ext.config.ts` instead of the project directory's `web-ext.config.ts` file. When placed in your home directory (`~/`), this config will be used by all WXT projects, so you only need to configure the binaries once.
:::
### Other options
You can customize other options as well, like startup URLs, profiles, or additional command line arguments:
For a full list of options, see the [API Reference](/api/wxt/interfaces/ExtensionRunnerConfig).
## Reload the Extension
Normally, to manually reload an extension, you have to visit `chrome://extensions` and click the reload button for your extension.
When running `wxt` command to start the dev server, WXT adds a keyboard shortcut `Alt+R`, that reloads the extension when pressed, without visiting `chrome://extensions`. This can also be customized or disabled:
```ts [wxt.config.ts]
import { defineConfig } from 'wxt';
export default defineConfig({
dev: {
reloadCommand: 'Alt+T', // false, to disable
},
});
```
:::info
This shortcut is only available during development, and is not be added to your extension when running `wxt build` or `wxt-zip`.
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](/entrypoints/background) documentation for a full list of recognized entrypoint filenames.
:::
## Entrypoint Options
Some entrypoints, like content scripts, actions, or the background, can receive additional options.
In HTML files, options are listed as `meta` tags:
```html
<html>
<head>
<!-- Defining the popup's "default_icon" field -->
ℹ Building chrome-mv3 for production with Vite 5.0.5
✖ Command failed after 360 ms
[8:55:54 AM] ERROR entrypoints/content.ts: Cannot use imported variable "GOOGLE_MATCHES" before main function. See https://wxt.dev/guide/entrypoints.html#side-effects
```
This throws an error because WXT needs to import each entrypoint during the build process to extract its definition (containing the `match`, `runAt`, `include`/`exclude`, etc.) to render the `manifest.json` correctly. Before loading an entrypoint, a transformation is applied to remove all imports. This prevents imported modules (local or NPM) with side-effects from running during the build process, potentially throwing an error.
:::details Why?
When importing your entrypoint to get its definition, the file is imported in a **_node environment_**, and doesn't have access to the `window`, `chrome`, or `browser` globals a web extension usually has access to. If WXT doesn't remove all the imports from the file, the imported modules could try and access one of these variables, throwing an error.
:::
:::warning
See [`wxt-dev/wxt#336`](https://github.com/wxt-dev/wxt/issues/336) to track the status of this bug.
:::
Usually, this error occurs when you try to extract options into a shared file or try to run code outside the `main` function. To fix the example from above, use literal values when defining an entrypoint instead of importing them:
Only MV3 support ESM background scripts/service workers. When targeting MV2, the `type` option is ignored and the background is always bundled into a single file as IIFE.
:::
## Content Scripts
Coming soon. Follow [Content Script ESM Support #357](https://github.com/wxt-dev/wxt/issues/357) for updates.
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.
During development, WXT will use any of the below packages to automatically open a browser with your extension installed.
- [`web-ext` by Mozilla](https://www.npmjs.com/package/web-ext)
Just install the dependency you want WXT to use to open the browser.
## `web-ext` Usage
> See the [API Reference](/api/reference/wxt/interfaces/WebExtConfig) for a full list of config.
### 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]
import { defineWebExtConfig } from 'wxt';
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"
},
});
```
```ts [wxt.config.ts]
export default defineConfig({
webExt: {
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.
To persist data, set the `--user-data-dir` flag in any of the config files mentioned above:
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 don't want to uninstall `web-ext`, like to test in your normal profile, you can do so via `disabled: true`:
```ts [web-ext.config.ts]
import { defineWebExtConfig } from 'wxt';
export default defineWebExtConfig({
disabled: true,
});
```
### Enabling Chrome Features
Some APIs are disabled in Chrome during development because of the default flags `web-ext` uses to launch Chrome, like the [Prompt API](https://developer.chrome.com/docs/ai/prompt-api).
If your extension depends on new features or services, you can enable them via `chromiumArgs`:
There is no comprehensive list of what feature flags enable what APIs and services.
Alternatively, if you can't find a flag that enables a feature you're looking for, [disable the opening the browser during development](#disable-opening-browser) and use your regular chrome profile for development.
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!_** See [Entrypoint Limitations](/guide/essentials/extension-apis#entrypoint-limitations) for more details.
:::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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