safe-wallet/specs/004-migrate-no-fee-campaign/quickstart.md

Quickstart: Migrate No Fee Campaign to Feature Architecture

Date: 2025-01-27
Feature: 004-migrate-no-fee-campaign

Overview

This guide provides step-by-step instructions for migrating the No Fee Campaign feature to the new Feature Architecture pattern. The migration maintains 100% functional parity while enabling lazy loading and proper code-splitting.

Prerequisites

• Feature architecture infrastructure (@/features/__core__) available
• createFeatureHandle helper function working
• ESLint restricted import rules configured
• Feature flag FEATURES.NO_FEE_NOVEMBER exists
• Semantic mapping 'no-fee-campaign': FEATURES.NO_FEE_NOVEMBER exists in createFeatureHandle.ts

Migration Steps

Step 1: Create Feature Contract

Create apps/web/src/features/no-fee-campaign/contract.ts:

import type NoFeeCampaignBanner from './components/NoFeeCampaignBanner'
import type NoFeeCampaignTransactionCard from './components/NoFeeCampaignTransactionCard'
import type GasTooHighBanner from './components/GasTooHighBanner'

export interface NoFeeCampaignContract {
  NoFeeCampaignBanner: typeof NoFeeCampaignBanner
  NoFeeCampaignTransactionCard: typeof NoFeeCampaignTransactionCard
  GasTooHighBanner: typeof GasTooHighBanner
}

Step 2: Create Feature Implementation

Create apps/web/src/features/no-fee-campaign/feature.ts:

import type { NoFeeCampaignContract } from './contract'

// Direct imports - this file is already lazy-loaded
import NoFeeCampaignBanner from './components/NoFeeCampaignBanner'
import NoFeeCampaignTransactionCard from './components/NoFeeCampaignTransactionCard'
import GasTooHighBanner from './components/GasTooHighBanner'

// Flat structure - naming conventions determine stub behavior
export default {
  NoFeeCampaignBanner,
  NoFeeCampaignTransactionCard,
  GasTooHighBanner,
} satisfies NoFeeCampaignContract

Step 3: Create Public API

Update apps/web/src/features/no-fee-campaign/index.ts:

import { createFeatureHandle } from '@/features/__core__'
import type { NoFeeCampaignContract } from './contract'

// Feature handle - uses semantic mapping (no-fee-campaign → FEATURES.NO_FEE_NOVEMBER)
export const NoFeeCampaignFeature = createFeatureHandle<NoFeeCampaignContract>('no-fee-campaign')

// Export contract type
export type { NoFeeCampaignContract } from './contract'

// Export hooks directly (always loaded, not in contract)
export { useIsNoFeeCampaignEnabled } from './hooks/useIsNoFeeCampaignEnabled'
export { useNoFeeCampaignEligibility } from './hooks/useNoFeeCampaignEligibility'
export { useGasTooHigh } from './hooks/useGasTooHigh'

Step 4: Update Consumer Code

Update all consumers to use useLoadFeature() pattern:

Before (direct import - VIOLATION)::

import NoFeeCampaignBanner from '@/features/no-fee-campaign/components/NoFeeCampaignBanner'
import { useNoFeeCampaignEligibility } from '@/features/no-fee-campaign/hooks/useNoFeeCampaignEligibility'

After:

import { NoFeeCampaignFeature, useNoFeeCampaignEligibility } from '@/features/no-fee-campaign'
import { useLoadFeature } from '@/features/__core__'

function MyComponent() {
  // Prefer destructuring for cleaner component usage
  const { NoFeeCampaignBanner } = useLoadFeature(NoFeeCampaignFeature)
  const eligibility = useNoFeeCampaignEligibility()

  return <NoFeeCampaignBanner />
}

Consumer locations to update:

1. apps/web/src/components/dashboard/index.tsx
2. apps/web/src/components/tx-flow/actions/Execute/ExecuteForm.tsx
3. apps/web/src/components/tx/ExecutionMethodSelector/index.tsx
4. apps/web/src/components/tx-flow/flows/TokenTransfer/CreateTokenTransfer.tsx
5. apps/web/src/pages/balances/index.tsx

Step 5: Verify Migration

Run quality gates:

# Type check
yarn workspace @safe-global/web type-check

# Lint (should show no restricted import warnings)
yarn workspace @safe-global/web lint

# Format
yarn workspace @safe-global/web prettier

# Tests (all should pass)
yarn workspace @safe-global/web test

Step 6: Verify Bundle Splitting

Build and verify code-splitting:

yarn workspace @safe-global/web build

# Check that No Fee Campaign code is in separate chunk
ls -la apps/web/.next/static/chunks/ | grep -i no-fee

Key Patterns

Component Usage

// Prefer destructuring for cleaner component usage
// Components render null when not ready (no check needed)
const { NoFeeCampaignBanner } = useLoadFeature(NoFeeCampaignFeature)
return <NoFeeCampaignBanner onDismiss={handleDismiss} />

Hook Usage

// Hooks imported directly, always safe to call
import { useNoFeeCampaignEligibility } from '@/features/no-fee-campaign'

const { isEligible, remaining, limit } = useNoFeeCampaignEligibility()

Explicit State Handling

const noFeeFeature = useLoadFeature(NoFeeCampaignFeature)

if (noFeeFeature.$isDisabled) return null
if (!noFeeFeature.$isReady) return <Skeleton />

// Destructure after state checks
const { NoFeeCampaignBanner } = noFeeFeature
return <NoFeeCampaignBanner />

Common Pitfalls

1. Don't use lazy() in feature.ts - The entire feature is already lazy-loaded
2. Don't include hooks in contract - Export them directly from index.ts
3. Don't nest structure - Use flat structure in contract and feature.ts
4. Don't import from internal folders - Use feature handle and direct hook imports
5. Don't change business logic - Maintain 100% functional parity

Verification Checklist

• contract.ts created with flat structure
• feature.ts created with direct imports
• index.ts exports feature handle and hooks
• All consumers updated to use useLoadFeature()
• Type check passes
• Lint passes (no restricted import warnings)
• Tests pass
• Bundle analysis shows code-splitting
• Feature works identically to before migration

Next Steps

After migration:

1. Verify all acceptance scenarios from spec
2. Run bundle analysis to confirm code-splitting
3. Test on chains with feature enabled and disabled
4. Update Storybook stories if needed
5. Document any edge cases discovered