Protocol Designer

Protocol Designer — Application-Specific Conventions

General TypeScript, React, styling, testing, import, and tooling conventions are in the opentrons-typescript skill. This file covers only what is unique to the protocol-designer package.

Project Overview

Protocol Designer (PD) is a React + Redux + React Router + TypeScript web app for designing Opentrons liquid-handling protocols. It depends on @opentrons/components, @opentrons/shared-data, and @opentrons/step-generation. It follows an atomic design system.

Redux Architecture

PD uses Redux (legacy createStore) with redux-thunk and reselect. The store shape is BaseState in src/types.ts.

Slices

Each slice directory contains reducers/, actions/, selectors/, and types.ts:

Middleware

• timelineMiddleware — generates robot state timeline from steps
• trackEventMiddleware — analytics event tracking
• thunk — async action support

Selectors

Use reselect createSelector for all derived state. Per-slice selectors go in selectors/ directories. Cross-slice selectors go in src/top-selectors/.

import { createSelector } from 'reselect'

export const getLabwareNicknamesById = createSelector(
  getLabwareEntities,
  labwareEntities => mapValues(labwareEntities, e => e.nickname)
)

Thunks

import type { ThunkAction } from '/protocol-designer/types'

export const myThunk = (): ThunkAction<any> => (dispatch, getState) => {
  const state = getState()
  dispatch({ type: 'MY_ACTION', payload: someSelector(state) })
}

Step & Timeline System

Core Concepts

• Steps: User-created protocol actions (move liquid, set temperature, pause, etc.)
• Timeline: Array of "frames" — each frame has robotState and commands
• Step forms: Redux state in stepForms.savedStepForms (keyed by step ID)
• Ordered steps: stepForms.orderedStepIds array

Step Form Flow

1. Step form data → stepFormToArgs() → command args
2. Command args → @opentrons/step-generation command creators → protocol commands
3. Commands → commandCreatorsTimeline() → timeline with robot state

Entities

Normalized by ID in Redux:

• labwareInvariantProperties — labware on deck
• pipetteInvariantProperties — pipettes by mount
• moduleInvariantProperties — hardware modules

Access via selectors: getLabwareEntities, getPipetteEntities, getModuleEntities.

Pages

Pages live in src/pages/:

• Designer/ — main protocol design canvas and step editing
• Landing/ — start screen
• Liquids/ — liquid definitions management
• ProtocolOverview/ — protocol summary
• Settings/ — user settings
• Hardware/ — hardware configuration
• Onboarding/ — first-run flow

PD-Specific File Conventions

Feature directories use kebab-case matching the Redux slice name: step-forms/, file-data/, labware-ingred/, well-selection/, etc.

The /protocol-designer/ path alias maps to src/. Use it for imports across feature directories:

import { getFileMetadata } from '/protocol-designer/file-data/selectors'

import type { BaseState } from '/protocol-designer/types'

Internationalization

Uses react-i18next. Translation files in src/assets/localization/.

Common namespaces: 'starting_deck_state', 'protocol_steps', 'shared', 'application'.

const { t } = useTranslation(['protocol_steps', 'shared'])
return (
  <>
    <span>{t('step_title')}</span>
   <span>{t('shared:step_body')}</span>
  </>
 )

Always use translation keys for user-facing strings — never hardcode display text.

PD Testing

Use renderWithProviders from protocol-designer/src/__testing-utils__/:

import { renderWithProviders } from '/protocol-designer/__testing-utils__'

PD Makefile Targets

Run from the protocol-designer/ directory:

# Run a specific test file
make test tests="src/components/organisms/__tests__/MyComponent.test.tsx"

# Run vitest directly from monorepo root
pnpm vitest protocol-designer/src/step-forms/

Environment Variables

PD feature flags use OT_PD_* env vars, injected at build time via Vite define. NODE_OPTIONS=--max-old-space-size=8192 is set automatically by the Makefile for dev, build, and serve.