Sheet JS

Open Source Components

In building SheetJS, we built many smaller components to solve specific challenges. Many of these are useful to the community at large on their own. We have tried to split off specific components into their own projects so others can benefit from our development efforts. Many of these projects have revealed insights that were later copied or used in other major products.

CRC-32 in JS and ADLER-32 in JS

Both algorithms appear in the ZIP format as well as other places where short checksums are needed. With some careful observations, our JS implementations are competitive with fine-tuned C implementations. (CRC-32 algorithm comparison). The popular React framework uses a modified version of ADLER-32

printf in JS

The printf family of functions are familiar for every C developer and the JS implementation lets us reproduce the exact output an equivalent C program would generate.


Community code is licensed under the Apache 2.0 License
All other code is subject to SheetJS LLC Software License Agreement