285 lines
8.2 KiB
Markdown
285 lines
8.2 KiB
Markdown
# ⏳ tiktoken
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tiktoken is a [BPE](https://en.wikipedia.org/wiki/Byte_pair_encoding) tokeniser for use with
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OpenAI's models, forked from the original tiktoken library to provide NPM bindings for Node and other JS runtimes.
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The open source version of `tiktoken` can be installed from NPM:
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```
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npm install @dqbd/tiktoken
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```
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## Usage
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Basic usage follows, which includes all the OpenAI encoders and ranks:
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```typescript
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import assert from "node:assert";
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import { get_encoding, encoding_for_model } from "@dqbd/tiktoken";
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const enc = get_encoding("gpt2");
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assert(
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new TextDecoder().decode(enc.decode(enc.encode("hello world"))) ===
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"hello world"
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);
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// To get the tokeniser corresponding to a specific model in the OpenAI API:
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const enc = encoding_for_model("text-davinci-003");
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// Extend existing encoding with custom special tokens
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const enc = encoding_for_model("gpt2", {
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"<|im_start|>": 100264,
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"<|im_end|>": 100265,
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});
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// don't forget to free the encoder after it is not used
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enc.free();
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```
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In constrained environments (eg. Edge Runtime, Cloudflare Workers), where you don't want to load all the encoders at once, you can use the lightweight WASM binary via `@dqbd/tiktoken/lite`.
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```typescript
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const { Tiktoken } = require("@dqbd/tiktoken/lite");
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const cl100k_base = require("@dqbd/tiktoken/encoders/cl100k_base.json");
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const encoding = new Tiktoken(
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cl100k_base.bpe_ranks,
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cl100k_base.special_tokens,
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cl100k_base.pat_str
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);
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const tokens = encoding.encode("hello world");
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encoding.free();
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```
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If you want to fetch the latest ranks, use the `load` function:
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```typescript
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const { Tiktoken } = require("@dqbd/tiktoken/lite");
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const { load } = require("@dqbd/tiktoken/load");
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const registry = require("@dqbd/tiktoken/registry.json");
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const models = require("@dqbd/tiktoken/model_to_encoding.json");
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async function main() {
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const model = await load(registry[models["gpt-3.5-turbo"]]);
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const encoder = new Tiktoken(
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model.bpe_ranks,
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model.special_tokens,
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model.pat_str
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);
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const tokens = encoding.encode("hello world");
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encoder.free();
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}
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main();
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```
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If desired, you can create a Tiktoken instance directly with custom ranks, special tokens and regex pattern:
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```typescript
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import { Tiktoken } from "../pkg";
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import { readFileSync } from "fs";
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const encoder = new Tiktoken(
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readFileSync("./ranks/gpt2.tiktoken").toString("utf-8"),
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{ "<|endoftext|>": 50256, "<|im_start|>": 100264, "<|im_end|>": 100265 },
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"'s|'t|'re|'ve|'m|'ll|'d| ?\\p{L}+| ?\\p{N}+| ?[^\\s\\p{L}\\p{N}]+|\\s+(?!\\S)|\\s+"
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);
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```
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Finally, you can a custom `init` function to override the WASM initialization logic for non-Node environments. This is useful if you are using a bundler that does not support WASM ESM integration.
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```typescript
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import { get_encoding, init } from "@dqbd/tiktoken/init";
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async function main() {
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const wasm = "..."; // fetch the WASM binary somehow
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await init((imports) => WebAssembly.instantiate(wasm, imports));
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const encoding = get_encoding("cl100k_base");
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const tokens = encoding.encode("hello world");
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encoding.free();
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}
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main();
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```
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## Compatibility
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As this is a WASM library, there might be some issues with specific runtimes. If you encounter any issues, please open an issue.
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| Runtime | Status | Notes |
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| ---------------------------- | ------ | ------------------------------------------ |
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| Node.js | ✅ | |
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| Bun | ✅ | |
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| Vite | ✅ | See [here](#vite) for notes |
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| Next.js | ✅ | See [here](#nextjs) for notes |
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| Create React App (via Craco) | ✅ | See [here](#create-react-app) for notes |
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| Vercel Edge Runtime | ✅ | See [here](#vercel-edge-runtime) for notes |
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| Cloudflare Workers | ✅ | See [here](#cloudflare-workers) for notes |
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| Deno | ❌ | Currently unsupported |
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### [Vite](#vite)
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If you are using Vite, you will need to add both the `vite-plugin-wasm` and `vite-plugin-top-level-await`. Add the following to your `vite.config.js`:
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```js
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import wasm from "vite-plugin-wasm";
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import topLevelAwait from "vite-plugin-top-level-await";
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import { defineConfig } from "vite";
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export default defineConfig({
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plugins: [wasm(), topLevelAwait()],
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});
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```
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### [Next.js](#nextjs)
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Both API routes and `/pages` are supported with the following `next.config.js` configuration.
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```typescript
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// next.config.json
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const config = {
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webpack(config, { isServer, dev }) {
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config.experiments = {
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asyncWebAssembly: true,
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layers: true,
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};
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return config;
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},
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};
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```
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Usage in pages:
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```tsx
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import { get_encoding } from "@dqbd/tiktoken";
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import { useState } from "react";
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const encoding = get_encoding("cl100k_base");
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export default function Home() {
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const [input, setInput] = useState("hello world");
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const tokens = encoding.encode(input);
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return (
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<div>
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<input
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type="text"
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value={input}
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onChange={(e) => setInput(e.target.value)}
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/>
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<div>{tokens.toString()}</div>
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</div>
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);
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}
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```
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Usage in API routes:
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```typescript
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import { get_encoding } from "@dqbd/tiktoken";
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import { NextApiRequest, NextApiResponse } from "next";
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export default function handler(req: NextApiRequest, res: NextApiResponse) {
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const encoding = get_encoding("cl100k_base");
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const tokens = encoding.encode("hello world");
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encoding.free();
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return res.status(200).json({ tokens });
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}
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```
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### [Create React App](#create-react-app)
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By default, the Webpack configugration found in Create React App does not support WASM ESM modules. To add support, please do the following:
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1. Swap `react-scripts` with `craco`, using the guide found here: https://craco.js.org/docs/getting-started/.
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2. Add the following to `craco.config.js`:
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```js
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module.exports = {
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webpack: {
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configure: (config) => {
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config.experiments = {
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asyncWebAssembly: true,
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layers: true,
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};
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// turn off static file serving of WASM files
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// we need to let Webpack handle WASM import
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config.module.rules
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.find((i) => "oneOf" in i)
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.oneOf.find((i) => i.type === "asset/resource")
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.exclude.push(/\.wasm$/);
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return config;
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},
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},
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};
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```
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### [Vercel Edge Runtime](#vercel-edge-runtime)
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Vercel Edge Runtime does support WASM modules by adding a `?module` suffix. Initialize the encoder with the following snippet:
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```typescript
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// @ts-expect-error
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import wasm from "@dqbd/tiktoken/lite/tiktoken_bg.wasm?module";
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import model from "@dqbd/tiktoken/encoders/cl100k_base.json";
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import { init, Tiktoken } from "@dqbd/tiktoken/lite/init";
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export const config = { runtime: "edge" };
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export default async function (req: Request) {
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await init((imports) => WebAssembly.instantiate(wasm, imports));
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const encoding = new Tiktoken(
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model.bpe_ranks,
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model.special_tokens,
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model.pat_str
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);
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const tokens = encoding.encode("hello world");
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encoding.free();
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return new Response(`${tokens}`);
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}
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```
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### [Cloudflare Workers](#cloudflare-workers)
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Similar to Vercel Edge Runtime, Cloudflare Workers must import the WASM binary file manually and use the `@dqbd/tiktoken/lite` version to fit the 1 MB limit. However, users need to point directly at the WASM binary via a relative path (including `./node_modules/`).
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Add the following rule to the `wrangler.toml` to upload WASM during build:
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```toml
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[[rules]]
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globs = ["**/*.wasm"]
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type = "CompiledWasm"
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```
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Initialize the encoder with the following snippet:
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```javascript
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import { init, Tiktoken } from "@dqbd/tiktoken/lite/init";
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import wasm from "./node_modules/@dqbd/tiktoken/lite/tiktoken_bg.wasm";
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import model from "@dqbd/tiktoken/encoders/cl100k_base.json";
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export default {
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async fetch() {
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await init((imports) => WebAssembly.instantiate(wasm, imports));
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const encoder = new Tiktoken(
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model.bpe_ranks,
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model.special_tokens,
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model.pat_str
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);
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const tokens = encoder.encode("test");
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encoder.free();
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return new Response(`${tokens}`);
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},
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};
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```
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## Acknowledgements
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- https://github.com/zurawiki/tiktoken-rs
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