tealchart

A fast, lightweight charting library for trading UIs — web (Canvas) and React Native (Skia). Ships with tealscript, its companion indicator/scripting package.

This is a mirror. It's a filtered, read/write view of an upstream monorepo. Contribute here normally (branch, PR, review); accepted changes are synced upstream. Everything needed to build and test lives in this repo — you don't need upstream access.

For contributor workflow details, see CONTRIBUTING.md. For coding agents and LLM tools, see AGENTS.md.

Packages

packages/tealchart    Charting library (web + React Native Skia)
packages/tealscript   Indicator / scripting engine used by tealchart

Develop

yarn install
yarn typecheck
yarn lint
yarn test

If this checkout is vendored into a React Native app, yarn install here can break that app — see Vendoring tealchart as source.

Using tealchart

// Web
import { createTealchartWidget } from '@tealstreet/tealchart';

// React Native (requires @shopify/react-native-skia + peers)
import { SkiaTealchart } from '@tealstreet/tealchart/native';

Vendoring tealchart as source

tealchart is not published as a built package yet, so React Native apps consume it as source — usually a submodule at vendor/tealchart with Metro aliases pointing at packages/tealchart/src. That puts tealchart's files outside the app's node_modules, and Metro resolves a bare import by walking up from the importing file's directory. vendor/tealchart/node_modules therefore wins over the app's copy.

That matters because yarn install in this repo — which you need for yarn typecheck, yarn lint, and yarn test above — installs tealchart's own react, react-native, react-native-reanimated, react-native-worklets, and react-native-gesture-handler. The consuming app then loads a second copy of packages that must be singletons, bound to native code that only ever registered the first.

A duplicate react-native-worklets is the dangerous one: it creates a second worklet runtime, which corrupts the Hermes heap. The app dies with EXC_BAD_ACCESS in hermes::vm::* at a different address and a different call site on every launch, with no JavaScript error and nothing pointing at module resolution. A duplicate react-native-reanimated is milder and usually surfaces as "react-native-reanimated is not installed!".

Guard against it in the consuming app's metro.config.js by resolving bare specifiers from the vendor tree as if they were required from the app root:

const vendorRoot = path.join(__dirname, 'vendor/tealchart');
const appRootOrigin = path.join(__dirname, 'package.json');

config.resolver.resolveRequest = (context, moduleName, platform) => {
  if (
    context.originModulePath?.startsWith(vendorRoot) &&
    !moduleName.startsWith('.') &&
    !path.isAbsolute(moduleName)
  ) {
    try {
      return context.resolveRequest(
        { ...context, originModulePath: appRootOrigin },
        moduleName,
        platform,
      );
    } catch {
      // Vendor-only dependency: fall through to default resolution.
    }
  }
  return context.resolveRequest(context, moduleName, platform);
};

Deleting vendor/tealchart/node_modules also fixes it, but only until the next time someone runs the checks in this repo. Prefer the resolver guard.

This section becomes unnecessary once tealchart ships as a built package.

Contributing

Branch off master, open a PR, and wait for a maintainer to review and merge. Merged changes sync upstream automatically; you do not need upstream access.

If Git reports a conflict, stop and ask in the PR. Do not commit directly to master.

Simple workflow with just

Install just and the GitHub CLI once:

brew install just gh
gh auth login

Start from the newest mirror master and create a feature branch:

just start feat/my-change

Do your work, then run the normal checks:

just check

Push and open a PR:

just pr

After the PR is merged, return to a clean master:

just done feat/my-change

Same workflow with plain Git

Start from the newest mirror master:

git switch master
git pull --ff-only origin master
git switch -c feat/my-change

Push and open a PR:

git push -u origin HEAD
gh pr create --fill

After the PR is merged:

git switch master
git pull --ff-only origin master
git branch -d feat/my-change

License

MIT — see LICENSE.