This is the public documentation for Expo, its SDK, client, and services, like EAS.
This documentation is built using Next.js and you can access it online at https://docs.expo.dev/.
Note Contributors: Please make sure that you edit the docs in the
pages/versions/unversioned
directory if you want your changes to apply to the next SDK version too!
Note If you are looking for Expo Documentation Writing Style guidelines, please refer Expo Documentation Style Guide.
Download the copy of this repository.
git clone https://github.com/expo/expo.git
Then cd
into the docs
directory and install dependencies with:
yarn
Then you can run the app with (make sure you have no server running on port 3002
):
yarn run dev
Now the documentation is running at http://localhost:3002, and any changes you make to markdown or JavaScript files will automatically trigger reloads.
yarn run export
yarn run export-server
You can find the content source of the documentation inside the pages/
directory. Documentation is mostly written in markdown with the help of some React components (for Snack embeds, etc). Our API documentation can all be found under pages/versions/
; we keep separate versions of the documentation for each SDK version currently supported in Expo Go, see "A note about versioning" for more info. The routes and navbar are automatically inferred from the directory structure within versions
.
Note We are currently in the process of moving our API documentation to being auto-generated using
expotools
'sGenerateDocsAPIData
command.
Each markdown page can be provided metadata in the heading, distinguished by:
---
metadata: goes here
---
These metadata items include:
title
: Title of the page shown as the heading and in search results.description
: Description of the page shown in search results and open graph descriptions when the page is shared on social media sites.hideFromSearch
: Whether to hide the page from Algolia search results. Defaults tofalse
.hideInSidebar
: Whether to hide this page from the sidebar. Defaults tofalse
.hideTOC
: Whether to hide the table of contents (appears on the right sidebar). Defaults tofalse
.sidebar_title
: The title of the page to display in the sidebar. Defaults to the page title.maxHeadingDepth
: The max level of headings shown in Table of Content on the right side. Defaults to3
.
The docs are written with Next.js and TypeScript. If you need to make code changes, follow steps from the Running locally section, then open a separate terminal and run the TypeScript compiler in watch mode - it will watch your code changes and notify you about errors.
yarn watch
When you are done, you should run prettier
to format your code. Also, don't forget to run tests and linter before committing your changes.
yarn prettier
yarn test
yarn lint
These redirects are limited in their expressiveness - you can map a path to another path, but no regular expressions or anything are supported. See client-side redirects for more of that. Server-side redirects are re-created on each run of deploy.sh.
We currently do two client-side redirects, using meta tags with http-equiv="refresh"
:
/
->/versions/latest/
/versions
->/versions/latest
This method is not great for accessibility and should be avoided where possible.
Use these for more complex rules than one-to-one path-to-path redirect mapping. For example, we use client-side redirects to strip the .html
extension off, and to identify if the request is for a version of the documentation that we no longer support.
You can add your own client-side redirect rules in common/error-utilities.ts
.
We use Algolia as a main search results provider for our docs. Besides the query, results are also filtered based on the version
tag which represents the user current location. The tag set in the components/DocumentationPage.tsx
head.
In ui/components/CommandMenu/utils.ts
, you can see the facetFilters
set to [['version:none', 'version:{version}']]
. Translated to English, this means - search on all pages where version
is none
, or the currently selected version. Here are the rules we use to set this tag:
- all unversioned pages use the version tag
none
, - all versioned pages use the SDK version (e.g.
v46.0.0
orv47.0.0
), - all pages with
hideFromSearch: true
frontmatter entry don't have the version tag.
Currently, the base results for Expo docs are combined with other results from multiple sources, like:
- manually defined paths for Expo dashboard located in
ui/components/CommandMenu/expoEntries.ts
, - public Algolia index for React Native website,
- React Native directory public API, see the directory README.md for more details.
- You can't have curly brace without quotes: `{}` ->
{}
Expo's SDK is versioned so that apps made on old SDKs are still supported when new SDKs are released. The website documents previous SDK versions too.
Version names correspond to directory names under versions
.
unversioned
is a special version for the next SDK release. It is not included in production output. Additionally, any versions greater than the package.json version
number are not included in production output, so that it's possible to generate, test, and make changes to new SDK version docs during the release process.
latest
is an untracked folder which duplicates the contents of the folder matching the version number in package.json.
Sometimes you want to make an edit in version X
and have that edit also
be applied in versions Y, Z, ...
(say, when you're fixing documentation for an
API call that existed in old versions too). You can use the
./scripts/versionpatch.sh
utility to apply your git diff
in one version in
other versions. For example, to update the docs in unversioned
then apply it
on v8.0.0
and v7.0.0
, you'd do the following after editing the docs in
unversioned
such that it shows up in git diff
:
./scripts/versionpatch.sh unversioned v8.0.0 v7.0.0
Any changes in your git diff
outside the unversioned
directory are ignored
so don't worry if you have code changes or such elsewhere.
The docs are deployed automatically via a GitHub Action each time a PR with docs changes is merged to main
.
If you need to link from one MDX file to another, please use the static/full path to this file (avoid relative links):
- from: tutorial/button.mdx, to: introduction/expo.mdx ->
/introduction/expo
- from: index.mdx, to: guides/errors.mdx#tracking-js-errors ->
/guides/errors/#tracking-javascript-errors
You can validate all current links by running yarn lint-links
script.
When we release a new SDK, we copy the unversioned
directory, and rename it to the new version. Latest version of docs is read from package.json so make sure to update the version
key there as well.
Make sure to also grab the upgrade instructions from the release notes blog post and put them in upgrading-expo-sdk-walkthrough.mdx.
That's all you need to do. The versions
directory is listed on server start to find all available versions. The routes and navbar contents are automatically inferred from the directory structure within versions
.
Because the navbar is automatically generated from the directory structure, the default ordering of the links under each section is alphabetical. However, for many sections, this is not ideal UX. So, if you wish to override the alphabetical ordering, manipulate page titles in constants/navigation.js.
To render the app.json / app.config.js properties table, we currently store a local copy of the appropriate version of the schema.
If the schema is updated, in order to sync and rewrite our local copy, run yarn run schema-sync <SDK version integer>
or yarn run schema-sync unversioned
.
You can add images and assets to the public/static
directory. They'll be served by the production and staging servers at /static
.
- Record the video using QuickTime
- Install
ffmpeg
(brew install ffmpeg
) - Run
ffmpeg -i your-video-name.mov -vcodec h264 -acodec mp2 your-video-name.mp4
to convert to mp4. - If the width of the video is larger than ~1200px, then run this to shrink it:
ffmpeg -i your-video.mp4 -filter:v scale="1280:trunc(ow/a/2)*2" your-video-smaller.mp4
- Put the video in the appropriate location in
public/static/videos
and use it in your docs page MDX like this:
import Video from '~/components/plugins/Video';
// Change the path to point to the relative path to your video from within the `static/videos` directory
<Video file="guides/color-schemes.mp4" />;
Snacks are a great way to add instantly-runnable examples to our docs. The SnackInline
component can be imported to any markdown file, and used like this:
import SnackInline from '~/components/plugins/SnackInline';
<SnackInline label='My Example Label' dependencies={['array of', 'packages', 'this Snack relies on']}>
// All your JavaScript code goes in here
// You can use:
/* @info Some text goes here */
const myVariable = SomeCodeThatDoesStuff();
/* @end */
// to create hoverable-text, which reveals the text inside of `@info` onHover.
// You can use:
/* @hide Content that is still shown, like a preview. */
Everything in here is hidden in the example Snack until
you open it in snack.expo.dev
/* @end */
// to shorten the length of the Snack shown in our docs. Common example are hiding useless code in examples, like StyleSheets
</SnackInline>
Sometimes it's useful to show multiple ways of doing something, for instance maybe you'd like to have an example using a React class component, and also an example of a functional component.
The Tabs
plugin is really useful for this, and this is how you'd use it in a markdown file:
import { Tabs, Tab } from '~/ui/components/Tabs';
<Tabs>
<Tab label="Add 1 One Way">
addOne = async x => {
/* @info This text will be shown onHover */
return x + 1;
/* @end */
};
</Tab>
<Tab label="Add 1 Another Way">
addOne = async x => {
/* @info This text will be shown onHover */
return x++;
/* @end */
};
</Tab>
</Tabs>
n.b. The components should not be indented or they will not be parsed correctly.
To ignore a page from the search result, use hideFromSearch: true
on that page. This removes the <meta name="docsearch:version">
tag from that page and filters it from our facet-based search.
Please note that hideFromSearch
only prevents the page from showing up in the internal docs search (Algolia). The page will still show up in search engine results like Google.
For a page to be hidden even from search engine results, you need to edit the sitemap that is generated via our Next.js config (next.config.js).
Certain directories are excluded from the sidebar in order to prevent it from getting too long and unnavigable. You can find a list of these directories, and add new ones, in constants/navigation.js under hiddenSections
.
If you just want to hide a single page from the sidebar, set hideInSidebar: true
in the page metadata.
Whenever shell commands are used or referred, use Terminal
component to make the code snippets copy/pasteable. This component can be imported in any markdown file.
import { Terminal } from '~/ui/components/Snippet';
// for single command and one prop
<Terminal cmd={["$ npx expo install package"]} />
// for multiple commands
<Terminal cmd={[
"# Create a new native project",
"$ npx create-expo-app --template bare-minimum",
"",
"# If you don’t have expo-cli yet, get it",
"$ npm i -g expo-cli",
"",
]} cmdCopy="npx create-expo-app --template bare-minimum && npm i -g expo-cli" />
Please commit any sizeable diffs that are the result of prettier
separately to make reviews as easy as possible.
If you have a code block using /* @info */
highlighting, use {/* prettier-ignore */}
on the block and take care to preview the block in the browser to ensure that the indentation is correct - the highlighting annotation will sometimes swallow newlines.