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Local Installation

Check here for examples: https://github.com/naptha/tesseract.js/blob/master/docs/examples.md

In browser environment, tesseract.js simply provides the API layer. Internally, it opens a WebWorker to handle requests. That worker itself loads code from the Emscripten-built tesseract.js-core which itself is hosted on a CDN. Then it dynamically loads language files hosted on another CDN.

Because of this we recommend loading tesseract.js from a CDN. But if you really need to have all your files local, you can pass extra arguments to TesseractWorker to specify custom paths for workers, languages, and core.

In Node.js environment, the only path you may want to customize is languages/langPath.

const worker = await createWorker('eng', 1, {
  workerPath: 'https://cdn.jsdelivr.net/npm/[email protected]/dist/worker.min.js',
  langPath: 'https://tessdata.projectnaptha.com/4.0.0',
  corePath: 'https://cdn.jsdelivr.net/npm/[email protected]',
});

workerPath

A string specifying the location of the worker.js file.

langPath

A string specifying the location of the tesseract language files. Language file URLs are calculated according to the formula langPath + langCode + '.traineddata.gz'. If langPath is not specified by the user, then the correct language data will be automatically downloaded from the jsDelivr CDN.

corePath

A string specifying the location of the tesseract.js-core files, with default value 'https://cdn.jsdelivr.net/npm/[email protected]'.

If you set the corePath argument, be sure to set it to a directory that contains all 4 of these files:

  1. tesseract-core.wasm.js
  2. tesseract-core-simd.wasm.js
  3. tesseract-core-lstm.wasm.js
  4. tesseract-core-simd-lstm.wasm.js

Tesseract.js will pick the correct file based on your users' device and the createWorker options.

To avoid breaking old code, when corePath is set to a specific .js file (e.g. https://cdn.jsdelivr.net/npm/[email protected]/tesseract-core.wasm.js), it will load that file regardless of whether the users' device supports SIMD or not. This behavior only exists to preserve backwards compatibility—setting corePath to a specific .js file is strongly discouraged. Doing so will either result in much slower performance (if tesseract-core.wasm.js is specified) or failure to run on certain devices (if tesseract-core-simd.wasm.js is specified).