# Tesseract.js v5.0.0

- Product: Tesseract.js (https://whatsnew.fyi/product/tesseract-js)
- Vendor: naptha
- Date: 2023-09-28
- Version: v5.0.0
- Original notes: https://github.com/naptha/tesseract.js/releases/tag/v5.0.0
- Permalink: https://whatsnew.fyi/product/tesseract-js/releases/v5.0.0

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

---

- **changed** — File sizes reduced by 54% for English and 73% for Chinese
- **changed** — Worker memory utilization reduced from 311 MB to 164 MB (47% reduction)
- **fixed** — Made compatible with iOS 17
- **changed** — Language and OEM arguments now set in createWorker instead of loadLanguage and initialize
- **changed** — worker.initialize and worker.loadLanguage functions now do nothing
- **added** — worker.reinitialize function to reinitialize workers with different settings
- **changed** — corePath directory must now contain all 4 core files (tesseract-core.wasm.js, tesseract-core-simd.wasm.js, tesseract-core-lstm.wasm.js, tesseract-core-simd-lstm.wasm.js)
- **changed** — worker.detect function disabled by default, requiring legacyCore and legacyLang options to enable
- **changed** — Language data loaded from jsdelivr by default instead of GitHub pages
- **removed** — Separate development build that produced tesseract.dev.js and worker.dev.js

##### What's Changed

##### Major New Features
1. **Significantly** smaller file sizes
   1. 54% smaller file sizes for English, 73% smaller for Chinese (see #806 for details)
   2. This results in a **~50% decrease** in runtime for first-time users (who do not yet have the data downloaded/cached)
1. Significantly lower memory usage
   1. Worker memory utilization in the [web benchmark](https://github.com/naptha/tesseract.js/blob/dev/v5/benchmarks/browser/speed-benchmark.html) is reduced from 311 MB to 164 MB (47% reduction)
   2. The lower memory footprint makes it feasible to use more workers, significantly improving performance for projects that utilize [schedulers](https://github.com/naptha/tesseract.js/blob/master/docs/intro.md) for parallel processing
1. Compatible with iOS 17 (using default settings)
   1. iOS 17 broke compatibility with Tesseract.js v4--upgrading to v5 should resolve
      1. See discussion section below for details

##### Breaking Changes Impacting Many Users
1. `createWorker` arguments changed
   1. Setting non-default language and OEM now happens in `createWorker`
      1. E.g. `createWorker("chi_sim", 1)`
1. `worker.initialize` and `worker.loadLanguage` functions now do nothing and can be deleted from code
   1. Loading the language and initialization now occurs in `createWorker`
   4. Workers can be re-initialized with different settings using `worker.reinitialize`

In other words, code should be modified from this:

```
const worker = await Tesseract.createWorker();
await worker.loadLanguage('eng');
await worker.initialize('eng');
const ret = await worker.recognize(file);
```
To this:

```
const worker = await Tesseract.createWorker("eng");
const ret = await worker.recognize(file);
```


##### Breaking Changes Impacting Fewer Users
1. Users who manually set `corePath` will need to update the contents of their `corePath` directory
   1. `corePath` should point to a directory that contains **all 4** of the files below from Tesseract.js-core v5:
      1. `tesseract-core.wasm.js`
      2. `tesseract-core-simd.wasm.js`
      3. `tesseract-core-lstm.wasm.js`
      4. `tesseract-core-simd-lstm.wasm.js`
   1. Tesseract.js will automatically select the correct version to use 
1. `worker.detect` function disabled by default
   1. Orientation + script detection is a function of the Legacy model only, which is no longer included by default
   6. To enable, set arguments  `legacyCore: true` and `legacyLang: true` in `createWorker` options
      1. E.g. `Tesseract.createWorker("eng", 1, {legacyCore: true, legacyLang: true});`
1. Language of progress logs standardized
   1. This should only impact users who parse status logs (e.g. to update a loading bar)

##### Non-Breaking Changes
1. Language data loaded from `jsdelivr` by default (rather than GitHub pages)
   1. This should result in improved performance and uptime
1. Separate "development" build (that produced `tesseract.dev.js` and `worker.dev.js` removed
1. Documentation and examples were modified to prevent new users from using `Tesseract.recognize` and `Tesseract.detect`
   1. Users who already use these functions are encouraged to modify their code to use `worker.recognize` and `worker.detect` instead

Considering upgrading from v2 to v5?  See #771 for a full guide for updating. 

**Full Changelog**: https://github.com/naptha/tesseract.js/compare/v4.1.3...v5.0.0