dab-extension-shared-architecture

name	dab-extension-shared-architecture
description	Use when refactoring DAB VS Code extensions to shared packages, reducing duplicate code, choosing dependencies, or keeping extension bundles small.
license	MIT

DAB Extension Shared Architecture

Use when

• Moving logic from a child extension into shared/ or shared-database/.
• Auditing duplicated utilities across extensions.
• Deciding whether a helper belongs in an extension or shared package.
• Keeping VSIX output small while preserving runtime dependencies.

Shared package model

• shared/ publishes dab-vscode-shared for lightweight utilities used by many or future extensions.
• shared-database/ publishes dab-vscode-shared-database for SQL/database utilities and depends on mssql.
• Prefer shared/ for generic config, terminal, prompt, path, validation, and type helpers.
• Use shared-database/ only for database connectivity, metadata queries, and SQL-specific types.
• If a helper can be generic and useful to another or future extension, move it to shared even if only one extension needs it today.

Dependency rules

• All child extensions may depend on dab-vscode-shared when they need shared utilities.
• Only database-querying extensions should depend on dab-vscode-shared-database.
• Keep lightweight extensions out of shared-database to avoid shipping database driver weight unnecessarily.
• Check each extension's package.json before adding dependencies; existing manifests use both * and file:../shared patterns, so preserve local convention unless standardizing deliberately.

Refactor workflow

1. Search for duplicate utilities in child extension src/ folders.
2. Check shared/src/index.ts and shared-database/src/index.ts for existing exports before adding new ones.
3. Move generic logic into the appropriate shared package with tests.
4. Export the new API from the shared package entry point.
5. Update child extension imports to use dab-vscode-shared/... or dab-vscode-shared-database/....
6. Delete stale local duplicate code after the extension builds.
7. Run shared package tests and the affected extension build.

Common duplication targets

• Terminal command helpers should live under dab-vscode-shared/terminal.
• DAB config reading and path validation should live under dab-vscode-shared/config.
• Environment variable helpers should live under dab-vscode-shared/config or another shared module.
• MSSQL connection and metadata helpers should live under dab-vscode-shared-database.

VS Code API boundary

• Keep pure logic testable without importing vscode.
• Keep VS Code API integration in extension entry points or thin adapters.
• Do not move extension-specific command registration into shared packages.

Completion checks

• Shared code has tests when behavior changed.
• Duplicate child-extension code was removed.
• Affected extension still builds and imports shared code correctly.
• No lightweight extension gained avoidable database dependencies.