@sec-ant/barcode-detector
A Barcode Detection API polyfill that uses ZXing webassembly under the hood.
Install
To install, run the following command:
npm i @sec-ant/barcode-detector
Recommended Usage with Node + ESM
This package can be imported in three different ways:
Pure Module
import { BarcodeDetector } from "@sec-ant/barcode-detector/pure";
To avoid potential namespace collisions, you can also rename the export:
import { BarcodeDetector as BarcodeDetectorPolyfill } from "@sec-ant/barcode-detector/pure";
This approach is beneficial when you want to use a package to detect barcodes without polluting globalThis
, or when your runtime already provides an implementation of the Barcode Detection API, but you still want this package to function.
Side Effects
import "@sec-ant/barcode-detector/side-effects";
This approach is beneficial when you need a drop-in polyfill. If there's already an implementation of Barcode Detection API on globalThis
, this won't take effect (type declarations will, as we cannot optionally declare types). In such cases, please use the pure module instead.
Both
import { BarcodeDetector } from "@sec-ant/barcode-detector";
This approach combines the pure module and side effects.
Recommended Usage in Modern Browsers
For modern browsers that support ES modules, this package can be imported via the <script type="module">
tags:
-
Include side effects:
<script
type="module"
src="https://cdn.jsdelivr.net/npm/@sec-ant/barcode-detector@1.2/dist/es/side-effects.min.js"
></script>
<script type="module">
const barcodeDetector = new BarcodeDetector();
</script>
-
Script scoped access:
<script type="module">
import { BarcodeDetector } from "https://cdn.jsdelivr.net/npm/@sec-ant/barcode-detector@1.2/dist/es/pure.min.js";
const barcodeDetector = new BarcodeDetector();
</script>
-
With import maps:
<script type="importmap">
{
"imports": {
"@sec-ant/barcode-detector/pure": "https://cdn.jsdelivr.net/npm/@sec-ant/barcode-detector@1.2/dist/es/pure.min.js"
}
}
</script>
<script type="module">
import { BarcodeDetector } from "@sec-ant/barcode-detector/pure";
const barcodeDetector = new BarcodeDetector();
</script>
Usage with Legacy Compatibility
Starting from v1.2, this package supports IIFE and CJS build outputs for use cases that require legacy compatibility.
IIFE
For legacy browsers that lack support for module type <script>
tags, or for userscripts, IIFE is the preferred choice. Upon executing the IIFE script, a variable named BarcodeDetectionAPI
will be registered in the global.
<script src="https://cdn.jsdelivr.net/npm/@sec-ant/barcode-detector@1.2/dist/iife/pure.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/@sec-ant/barcode-detector@1.2/dist/iife/side-effects.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/@sec-ant/barcode-detector@1.2/dist/iife/index.min.js"></script>
CJS
This package can also be consumed as a commonjs package:
-
Vanilla Javascript:
const { BarcodeDetector } = require("@sec-ant/barcode-detector/pure");
-
With Typescript:
import { BarcodeDetector } from "@sec-ant/barcode-detector/pure";
{
"compilerOptions": {
"module": "CommonJS",
"moduleResolution": "Node",
"skipLibCheck": true
},
"include": ["src"]
}
setZXingModuleOverrides
In addition to BarcodeDetector
, this package exports another function called setZXingModuleOverrides
.
This package employs Sec-ant/zxing-wasm to enable the core barcode reading functionality. As a result, a .wasm
binary file is fetched at runtime. The default fetch path for this binary file is:
https://cdn.jsdelivr.net/npm/@sec-ant/zxing-wasm@<version>/dist/reader/zxing_reader.wasm
The setZXingModuleOverrides
function allows you to govern where the .wasm
binary is served from, thereby enabling offline use of the package, use within a local network, or within a site having strict CSP rules.
For instance, should you want to inline this .wasm
file in your build output for offline usage, with the assistance of build tools, you could try:
import wasmFile from "../node_modules/@sec-ant/zxing-wasm/dist/reader/zxing_reader.wasm?url";
import {
setZXingModuleOverrides,
BarcodeDetector,
} from "@sec-ant/barcode-detector/pure";
setZXingModuleOverrides({
locateFile: (path, prefix) => {
if (path.endsWith(".wasm")) {
return wasmFile;
}
return prefix + path;
},
});
const barcodeDetector = new BarcodeDetector();
Alternatively, the .wasm
file could be copied to your dist folder to be served from your local server, without incorporating it into the output as an extensive base64 data URL.
It's noteworthy that you'll always want to choose the correct version of the .wasm
file, so the APIs exported by it are exactly what the js code expected.
For more information on how to use this function, you can check the notes here and discussions here.
This function is exported from all the subpaths, including the side effects.
API
Please check the spec and MDN doc for more information.
Example
import "@sec-ant/barcode-detector/side-effects";
const barcodeDetector: BarcodeDetector = new BarcodeDetector({
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, as well as the build output, except for the parts listed below, is licensed under the MIT license.
Test samples and resources are collected from zxing-cpp/zxing-cpp, which is licensed under the Apache-2.0 license, and web-platform-tests/wpt, which is licensed under the 3-Clause BSD license.
This package has an indirect dependency on Sec-ant/zxing-wasm-build, which is licensed under the Apache-2.0 license.