NodeJS implementation of today's most used tokenizers, with a focus on performance and versatility. Bindings over the Rust implementation. If you are interested in the High-level design, you can go check it there.

Main features

• Train new vocabularies and tokenize using 4 pre-made tokenizers (Bert WordPiece and the 3 most common BPE versions).
• Extremely fast (both training and tokenization), thanks to the Rust implementation. Takes less than 20 seconds to tokenize a GB of text on a server's CPU.
• Easy to use, but also extremely versatile.
• Designed for research and production.
• Normalization comes with alignments tracking. It's always possible to get the part of the original sentence that corresponds to a given token.
• Does all the pre-processing: Truncate, Pad, add the special tokens your model needs.

Installation

npm install tokenizers@latest

Basic example

import { Tokenizer } from "tokenizers";

const tokenizer = await Tokenizer.fromFile("tokenizer.json");
const wpEncoded = await tokenizer.encode("Who is John?");

console.log(wpEncoded.getLength());
console.log(wpEncoded.getTokens());
console.log(wpEncoded.getIds());
console.log(wpEncoded.getAttentionMask());
console.log(wpEncoded.getOffsets());
console.log(wpEncoded.getOverflowing());
console.log(wpEncoded.getSpecialTokensMask());
console.log(wpEncoded.getTypeIds());
console.log(wpEncoded.getWordIds());

License

Apache License 2.0