https://github.com/webreflection/mini-coi
A minimalistic version of coi-serviceworker.
https://github.com/webreflection/mini-coi
Last synced: 11 months ago
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A minimalistic version of coi-serviceworker.
- Host: GitHub
- URL: https://github.com/webreflection/mini-coi
- Owner: WebReflection
- License: mit
- Created: 2023-07-26T14:27:54.000Z (about 3 years ago)
- Default Branch: main
- Last Pushed: 2025-07-14T08:47:12.000Z (about 1 year ago)
- Last Synced: 2025-07-14T11:36:53.761Z (about 1 year ago)
- Language: JavaScript
- Size: 22.5 KB
- Stars: 28
- Watchers: 3
- Forks: 3
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# mini-coi
This project ensures your browser's
[complicated Cross Origin Isolation (COI) settings](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/SharedArrayBuffer#security_requirements)
"just work"™ for web workers. This is especially useful when you have no
control over the HTTP headers returned by the server.
The simplest way to use mini-coi is to **place the `mini-coi.js` file in the
root of your website (i.e. `/`), and reference it as the first child tag in the
`` of your HTML documents**:
```html
```
For more complete technical details, read on...
## What is mini-coi?
A minimalistic *CLI* utility or a simplified version of [coi-serviceworker](https://github.com/gzuidhof/coi-serviceworker), with an optional `scope` attribute to define where Cross Origin Isolation should happen.
## CLI
Bootstrap a local server with all headers enforced:
```sh
npx mini-coi .
# the third argument is a path so ...
# npx mini-coi ./public/
# npx mini-coi ./test/
# ...
```
The *CLI* brings in what's possible already to do with [static-handler](https://github.com/WebReflection/static-handler/tree/main) by passing `--coi` by default.
## Service Worker
Allow headers in places like GitHub pages or any other server where you cannot change current headers:
```html
```
#### What's different from coi-serviceworker?
* no options at all: "*it just works*" ™
* always *require-corp* to have this working on Safari as well as Chrome or Firefox
* errors are just thrown in devtools
- - -
### How to use mini-coi as Service Worker
* the file **must be a local file**, you can't use any CDN or raw GitHub URL, you need to copy the file content locally [^1]
* the script *must not be a module*, it has to be exactly a `` at the top of your `` tag in your page (or in general before any other `script` or `link` or `style` is used, it can be after `meta` and `title` though)
[^1]: You can either use the *CLI* utility:
```sh
npx mini-coi -sw public/mini-coi.js
// or ...
npx mini-coi --service-worker public/mini-coi.js
```
Or you can grab the file from a CDN and save it locally:
```sh
# grab mini-coi.js and save it locally as mini-coi.js
curl -LO https://raw.githubusercontent.com/WebReflection/mini-coi/main/mini-coi.js
```