zxing-wasm

The library distinguishes between canonical names (e.g., QRCode, EAN13) and symbologies (e.g., EANUPC or QRCode).

• Symbology Roots: Represented in bold italic in documentation, these are group identifiers. Passing a symbology root to a reader matches any variant within that group.
• ReadResult.format: Returns the specific detected format (the variant) or the symbology root if no finer variant was identified.
• ReadResult.symbology: Always returns the symbology root.

Linear (1D) Barcodes

Supported formats include:

• Codabar
• Code39 (variants: Code39Std, Code39Ext)
• Code32
• PZN
• Code93
• Code128 (supports GS1)
• ITF (variants: ITF14)
• DataBar (variants: DataBarOmni, DataBarStk, DataBarStkOmni, DataBarLtd, DataBarExp, DataBarExpStk; supports GS1)
• EANUPC (variants: EAN13, EAN8, EAN5, EAN2; supports Retail)
• ISBN
• UPCA, UPCE
• Telepen (variants: TelepenAlpha, TelepenNumeric)
• OtherBarcode (variant: DXFilmEdge)

Matrix (2D) Barcodes

Supported formats include:

• PDF417 (variants: CompactPDF417, MicroPDF417)
• Aztec (variants: AztecCode, AztecRune; supports GS1)
• QRCode (variants: QRCodeModel1, QRCodeModel2, MicroQRCode, RMQRCode; supports GS1)
• DataMatrix (supports GS1)
• MaxiCode (Note: Reading MaxiCode requires a pure monochrome image with an unrotated/unskewed symbol and a sufficient white border).

To use the library in environments like Node.js, Bun, or Deno without a web server, you must manually provide the .wasm binary via prepareZXingModule overrides. Here are the recommended approaches for Node.js:

1. Using instantiateWasm: Manually call WebAssembly.instantiate with a buffer read from the filesystem.
2. Using wasmBinary: Pass the file buffer directly as an ArrayBuffer.
3. Using locateFile with Object URLs: Create a Blob URL from the file buffer and use locateFile to return it. Use the postRun hook to call URL.revokeObjectURL to free memory.
4. Using locateFile with Base64 Data URLs: (Not recommended) Convert the file to a Base64 string and return a data URL.

// Example: Using wasmBinary in Node.js
import { readFileSync } from "node:fs";
import { prepareZXingModule } from "zxing-wasm/reader";

prepareZXingModule({
  overrides: {
    wasmBinary: readFileSync("/path/to/the/zxing_reader.wasm")
      .buffer as ArrayBuffer,
  },
});

By default, zxing-wasm uses a jsDelivr CDN to fetch the required .wasm binary. To serve the .wasm file from your own server or a different CDN, use prepareZXingModule with an overrides object containing a locateFile function. This is necessary before calling any barcode reading or writing functions.

Important: Ensure the .wasm file version matches your zxing-wasm library version to avoid errors.

import {
  prepareZXingModule,
  writeBarcode,
  ZXING_WASM_VERSION,
} from "zxing-wasm";

// Override the locateFile function
prepareZXingModule({
  overrides: {
    locateFile: (path, prefix) => {
      if (path.endsWith(".wasm")) {
        return `https://unpkg.com/zxing-wasm@${ZXING_WASM_VERSION}/dist/full/${path}`;
      }
      return prefix + path;
    },
  },
});

// Call read or write functions afterward
const writeOutput = await writeBarcode("Hello world!");

Using zxing-wasm in WeChat mini programs requires specific configuration due to environment limitations:

1. Import Path: Use only the base zxing-wasm import path. zxing-wasm/reader and zxing-wasm/writer are not supported.
2. File Management: Manually copy node_modules/zxing-wasm/dist/full/zxing_full.wasm into your project directory.
3. Configuration: You must use prepareZXingModule to configure loading via WXWebAssembly.instantiate (the WeChat-specific WebAssembly API).
4. Polyfills: The library includes a minimal Blob polyfill, but a full-fledged Blob polyfill is recommended for overall stability.

// WeChat Mini Program configuration
prepareZXingModule({
  overrides: {
    instantiateWasm(imports, successCallback) {
      WXWebAssembly.instantiate("path/to/zxing_full.wasm", imports).then(
        ({ instance }) => successCallback(instance),
      );
      return {};
    },
  },
});