Sec-ant
barcode-detector
A Barcode Detection API ponyfill/polyfill that uses ZXing-C++ WebAssembly under the hood.
Supported barcode formats:
| Linear Barcode Formats | Matrix Barcode Formats | Special Barcode Formats |
|---|---|---|
codabar |
aztec |
linear_codes[^2] |
code_39 |
data_matrix |
matrix_codes[^3] |
code_93 |
maxi_code[^1] |
any[^4] |
code_128 |
pdf417 |
|
databar |
qr_code |
|
databar_limited |
micro_qr_code |
|
databar_expanded |
rm_qr_code |
|
dx_film_edge |
| | |
ean_8 |
| | |
ean_13 |
| | |
itf |
| | |
upc_a |
| | |
upc_e |
[^1]: Detection support for MaxiCode requires a pure monochrome image that contains an unrotated and unskewed symbol, along with a sufficient white border surrounding it.
[^2]: linear_codes is a shorthand for all linear barcode formats.
[^3]: matrix_codes is a shorthand for all matrix barcode formats.
[^4]: any is a shorthand for linear_codes and matrix_codes, i.e., all barcode formats. Note that you don't need to specify any in the formats option, as not providing the option also indicates detecting all barcode formats.
Install
To install, run the following command:
npm i barcode-detectorUsage
Ponyfill
import { BarcodeDetector } from "barcode-detector/ponyfill";To avoid potential namespace collisions, you can also rename the export:
import { BarcodeDetector as BarcodeDetectorPonyfill } from "barcode-detector/ponyfill";A ponyfill is a module required to be explicitly imported without introducing side effects. Use this subpath if you want to avoid polluting the global object with the BarcodeDetector class, or if you intend to use the implementation provided by this package instead of the native one.
Polyfill
import "barcode-detector/polyfill";This subpath is used to polyfill the native BarcodeDetector class. It will automatically register the BarcodeDetector class in the global object if it's not already present.
[!IMPORTANT]
The polyfill will opt in only if no
BarcodeDetectoris present inglobalThis. It basically works like this:import { BarcodeDetector } from "barcode-detector/ponyfill"; globalThis.BarcodeDetector ??= BarcodeDetector;Note that it doesn't check if the implementation is provided natively or by another polyfill. It also doesn't try to augment the existing implementation with all the barcode formats supported by this package. If you want all the features provided by this package, but you already have a native or another polyfilled
BarcodeDetector, you should use the ponyfill approach. You can register it to theglobalThisobject manually if you want to.
Ponyfill + Polyfill
import { BarcodeDetector } from "barcode-detector";This approach combines the ponyfill and polyfill approaches.
[!NOTE]
The
ponyfillsubpath was namedpureand thepolyfillsubpath was namedside-effectsin early versions. They are no longer recommended for use and are considered deprecated. Please use the new subpaths as described above.
<script type="module">
For modern browsers that support ES modules, this package can be imported via the <script type="module"> tags:
Include the polyfill:
<!-- register --> <script type="module" src="https://fastly.jsdelivr.net/npm/barcode-detector@3/dist/es/polyfill.min.js" ></script> <!-- use --> <script type="module"> const barcodeDetector = new BarcodeDetector(); </script>Script scoped access:
<script type="module"> import { BarcodeDetector } from "https://fastly.jsdelivr.net/npm/barcode-detector@3/dist/es/ponyfill.min.js"; const barcodeDetector = new BarcodeDetector(); </script>With import maps:
<!-- import map --> <script type="importmap"> { "imports": { "barcode-detector/ponyfill": "https://fastly.jsdelivr.net/npm/barcode-detector@3/dist/es/ponyfill.min.js" } } </script> <!-- script scoped access --> <script type="module"> import { BarcodeDetector } from "barcode-detector/ponyfill"; const barcodeDetector = new BarcodeDetector(); </script>
IIFE
For legacy browsers or userscripts that lack support for <script type="module"> tags, IIFE is the preferred choice. Upon executing the IIFE script, a variable named BarcodeDetectionAPI will be registered in the global window by var declaration.
<!--
IIFE ponyfill.js registers:
window.BarcodeDetectionAPI.BarcodeDetector
window.BarcodeDetectionAPI.prepareZXingModule
-->
<script src="https://fastly.jsdelivr.net/npm/barcode-detector@3/dist/iife/ponyfill.min.js"></script>
<!--
IIFE polyfill.js registers:
window.BarcodeDetector
window.BarcodeDetectionAPI.prepareZXingModule
-->
<script src="https://fastly.jsdelivr.net/npm/barcode-detector@3/dist/iife/polyfill.min.js"></script>
<!--
IIFE index.js registers:
window.BarcodeDetector
window.BarcodeDetectionAPI.BarcodeDetector
window.BarcodeDetectionAPI.prepareZXingModule
-->
<script src="https://fastly.jsdelivr.net/npm/barcode-detector@3/dist/iife/index.min.js"></script>prepareZXingModule
The core barcode reading functionality of this package is powered by zxing-wasm. Therefore, a .wasm binary file is fetched at runtime. By default, the .wasm serving path is initialized with a jsDelivr CDN URL. However, there're cases where this is not desired, such as the allowed serving path is white-listed by the Content Security Policy (CSP), or offline usage is required.
To customize the .wasm serving path, this package reexports prepareZXingModule along with ZXING_WASM_VERSION and ZXING_WASM_SHA256 from zxing-wasm. For more details on how to use them, please check Configuring .wasm Serving and Controlling .wasm Instantiation Timing and Caching sections in the zxing-wasm repository.
An example usage to override the .wasm serving path with an unpkg.com CDN url is as follows:
import {
BarcodeDetector,
ZXING_WASM_VERSION,
prepareZXingModule,
} from "barcode-detector/ponyfill";
// Override the locateFile function
prepareZXingModule({
overrides: {
locateFile: (path, prefix) => {
if (path.endsWith(".wasm")) {
return `https://unpkg.com/zxing-wasm@${ZXING_WASM_VERSION}/dist/reader/${path}`;
}
return prefix + path;
},
},
});
// Now you can create a BarcodeDetector instance
const barcodeDetector = new BarcodeDetector({
formats: ["qr_code"],
});[!Note] The
setZXingModuleOverridesmethod is deprecated in favor ofprepareZXingModule.
API
Please check the spec, MDN doc and Chromium implementation for more information.
An example usage is as follows:
import { BarcodeDetector } from "barcode-detector/ponyfill";
// check supported formats
const supportedFormats = await BarcodeDetector.getSupportedFormats();
const barcodeDetector: BarcodeDetector = new BarcodeDetector({
// make sure the formats are supported
formats: ["qr_code"],
});
const imageFile = await fetch(
"https://api.qrserver.com/v1/create-qr-code/?size=150x150&data=Hello%20world!",
).then((resp) => resp.blob());
barcodeDetector.detect(imageFile).then(console.log);License
The source code in this repository is licensed under the MIT license.