@signalsafe/simulator-react

React device simulator UI: session state, screen registry, template adapter, lint helpers, and optional developer tools. Built on @signalsafe/simulator-core for runtime stepping.

npm	@signalsafe/simulator-react
GitHub	SignalSafeSoftware/simulator-react
Peer deps	react, react-dom (no UI library required)

UI-kit agnostic

This package is UI-kit agnostic. It renders semantic HTML with stable simulator-* class hooks and optional render slots — it does not require Bootstrap, Material UI, or any other component library.

Host applications own styling. Provide CSS for simulator-* classes, or pass renderChoice / renderFeedback / renderContactsOverlay / renderIncomingCallExtra / hostOwnsPhoneContactDetail + onPhoneContactOpen to inject your UI kit's components. Semantic view hooks (simulator-runtime, simulator-phone, simulator-email, simulator-messages, …) are stable targets for host CSS and tests — you do not need DOM enhancers or MutationObserver to find simulator regions.

See docs/UI_KIT_AGNOSTIC_USAGE.md for layout hooks, semantic view hooks, slots, and DeliveryPlus migration guidance.

See docs/ERROR_BOUNDARIES.md for learner-safe error UI vs author/admin diagnostics.

What this package does

• Render SimulatorWithSession / PhoneSimulatorShell and registered scenario screens.
• Manage session state via simulatorSessionReducer (wraps core runtime dispatch).
• Adapt template detail → SimulatorTemplatePayload (templateDetailToPayload).
• Provide shallow lint (lintSimulatorPayload), reachability, deep-link, preview-fallback, and diff utilities.
• Optional SimulatorDeveloperToolsPanel for QA/debug views.

What this package does not do

• Routing, HTTP clients, authentication, or persistence.
• Trusted validation of arbitrary user-uploaded JSON beyond shallow lint — hosts must validate payloads before production use.
• Network I/O — wire onSimulatorEvent to your analytics/API.

Relationship to @signalsafe/simulator-core

Concern	Package
Headless session stepping, scores, outcomes	@signalsafe/simulator-core
React UI, reducer wiring, screens, lint banner	@signalsafe/simulator-react (this package)

Payload shape (high level)

Hosts supply a SimulatorTemplatePayload: TreeSpec wire plus simulator world sections (screens, contacts, branding hints, etc.). Use templateDetailToPayload to map API/template records into that shape, then lintSimulatorPayload for authoring warnings.

Install

npm install @signalsafe/simulator-react react react-dom

Use a modern ESM TypeScript setup. Style simulator UI via host CSS targeting simulator-* class hooks, or pass render slots for full UI-kit control (see UI_KIT_AGNOSTIC_USAGE.md).

Minimal example (plain HTML + host CSS)

No Bootstrap or other UI library is required:

import { useReducer } from 'react';
import {
    SimulatorWithSession,
    PhoneSimulatorShell,
    getInitialSessionState,
    simulatorSessionReducer,
    templateDetailToPayload,
    type SimulatorTemplateDetail,
} from '@signalsafe/simulator-react';

import './simulator-host.css'; // map .simulator-btn, .simulator-muted, etc.

function PlainSimulator({ detail }: { detail: SimulatorTemplateDetail }) {
    const payload = templateDetailToPayload(detail, {});
    const [state, dispatch] = useReducer(
        simulatorSessionReducer,
        getInitialSessionState(payload),
    );

    return (
        <PhoneSimulatorShell>
            <SimulatorWithSession state={state} dispatch={dispatch} />
        </PhoneSimulatorShell>
    );
}

Optional: Bootstrap in the host (not a package requirement)

If your app already uses Bootstrap, wire it via render slots — this is host-app code, not a package dependency:

import Button from 'react-bootstrap/Button';
import 'bootstrap/dist/css/bootstrap.min.css'; // host-owned CSS

<SimulatorWithSession
    state={state}
    dispatch={dispatch}
    renderChoice={({ label, onClick, tone }) => (
        <Button variant={tone ?? 'primary'} onClick={onClick}>{label}</Button>
    )}
/>;

Repository

Source code and issues are available at: https://github.com/SignalSafeSoftware/simulator-react

Source layout (this package)

Area	Location
Main barrel	src/index.ts
Session reducer	src/state/simulatorSessionReducer.ts
Template → payload adapter	src/adapters/templateToSession.ts (templateDetailToPayload)
Screen registry	src/screenRegistry/
Utilities	src/utils/ (lint, reachability, deep link, diff, contact search, …)

Integration pattern

Convert template detail to a payload, validate and optionally apply preview fallback, build initial state, then render the shell and session:

import { useReducer } from 'react';
import {
    SimulatorWithSession,
    PhoneSimulatorShell,
    SimulatorLintBanner,
    templateDetailToPayload,
    getInitialSessionState,
    simulatorSessionReducerWithLogging,
    lintSimulatorPayload,
    parseSimulatorSearchParams,
    applyDeepLinkToState,
    getDeepLinkContactsSearch,
    applyPreviewFallback,
    type SimulatorSessionState,
    type SimulatorDispatchAction,
    type SimulatorInteractionEvent,
    type SimulatorTemplateDetail,
} from '@signalsafe/simulator-react';

// `SimulatorTemplateDetail` is defined in `src/types/portableSimulator.ts`.
function SimulatorHost({ detail }: { detail: SimulatorTemplateDetail }) {
    const rawPayload = templateDetailToPayload(detail, {});
    const payload = applyPreviewFallback(rawPayload);
    const lint = lintSimulatorPayload(payload);
    const initialState = getInitialSessionState(payload);
    const [state, dispatch] = useReducer(simulatorSessionReducerWithLogging, initialState);

    return (
        <PhoneSimulatorShell>
            {lint.messages.length > 0 ? <SimulatorLintBanner messages={lint.messages} /> : null}
            <SimulatorWithSession state={state} dispatch={dispatch} />
        </PhoneSimulatorShell>
    );
}

Search / deep links: parseSimulatorSearchParams, applyDeepLinkToState, and getDeepLinkContactsSearch align URL query state with session state.

Compare two payloads

import { diffSimulatorPayloads, type SimulatorDiffItem } from '@signalsafe/simulator-react';

const items: SimulatorDiffItem[] = diffSimulatorPayloads(leftPayload, rightPayload);

Interaction events (host typing)

import type { HostSimulatorEventHandler } from '@signalsafe/simulator-react';

const onSimulatorEvent: HostSimulatorEventHandler = (event) => {
    /* forward to your API or analytics */
};

<SimulatorWithSession state={state} dispatch={dispatch} onSimulatorEvent={onSimulatorEvent} />;

Developer tools panel

import { SimulatorDeveloperToolsPanel } from '@signalsafe/simulator-react';

<SimulatorDeveloperToolsPanel
    developerTools={{ preset: 'qa', sections: { reachability: true } }}
    payload={state.payload}
    timelineEntries={timelineEntries}
    runtimeIssues={runtimeIssues}
/>;

Subpath exports (package.json)

Imports outside the main barrel are explicit and versioned in exports:

Import	Purpose
@signalsafe/simulator-react/utils/validateSimulatorPayload	JSON-schema style validation helper
@signalsafe/simulator-react/utils/simulatorPreviewReport	Authoring / preview report builder
@signalsafe/simulator-react/utils/simulatorRealismChecks	QA / fixture realism checks (not on main barrel)
@signalsafe/simulator-react/utils/previewFallbackWorld	Preview fallback helpers + PREVIEW_PLACEHOLDER_ID_PREFIX

Other deep import paths are unsupported. Prefer the main barrel for app/runtime UI.

Tests

yarn test

Boundaries

• In scope: UI and state under src/, main barrel exports, and documented exports subpaths in package.json.
• Out of scope: routing, HTTP, auth — host apps supply payload and event handlers.
• Side effects: sideEffects: false — hosts supply layout/styling (CSS or UI kit) for simulator-* hooks and optional render slots.

Development

Requires Node.js >=22.12.0 (engines.node). CI runs checks, tests, and smoke on Node 22 and 24; publish uses Node 24. Node 20 is no longer supported (GitHub Actions Node 20 deprecation).

yarn build uses tsconfig.build.json and resolves @signalsafe/* from node_modules. Ecosystem sibling paths in tsconfig.json apply to local typecheck/tests only.

yarn install
yarn build
yarn test
yarn typecheck

Security

See SECURITY.md. Treat scenario payloads as trusted authoring content unless the host validates them. Gate learner-facing error detail in production hosts.

Changelog and releases

• CHANGELOG.md
• RELEASING.md