Background & Motivation

Developers writing azd hooks in JavaScript need the same zero-config experience delivered for Python in Phase 1. JavaScript is one of the most popular languages in the Azure ecosystem, and many azd users already have Node.js projects.

Parent Epic: #7435 — Multi-Language Hook Support
Phase 1 PR: #7451 — delivered the extensible framework and Python support

User Story

As an azd user, I want to write hook scripts in JavaScript (.js files) so that I can use my preferred language for pre/post-provisioning and deployment automation.

Existing Infrastructure (from Phase 1)

The following already exist and are shared by all new executors:

• HookExecutor interface (pkg/tools/script.go) — Prepare/Execute/Cleanup lifecycle
• HookKind constant js (pkg/tools/language/executor.go)
• InferKindFromPath() — maps .js→js
• Project discovery (pkg/tools/language/project_discovery.go) — walk-up for package.json
• IoC-based executor resolution in hooks_runner.go
• node.Cli singleton in cmd/container.go
• Schema support for kind: js in azure.yaml.json
• ExecutionContext with Cwd, EnvVars, BoundaryDir, etc.

Solution Approach

• Create jsExecutor in pkg/tools/language/js_executor.go implementing HookExecutor
• Prepare():
  • Validate Node.js is installed via existing node.Cli.CheckInstalled() — hard error with ErrorWithSuggestion if missing (include install URL)
  • Use DiscoverProjectFile() with package.json to find project root
  • If package.json found: auto-detect package manager from lock files (npm/pnpm/yarn) using existing node.Cli detection, then run install
  • If standalone (no package.json): skip dependency installation
• Execute():
  • With project: run node script.js with project's node_modules available
  • Standalone: run node script.js directly
  • Pass environment variables via ExecutionContext.EnvVars
  • Respect ExecutionContext.Cwd for working directory
  • Respect ExecutionContext.Interactive for stdin/stdout
• Cleanup(): No-op (no temp files created)
• Register "js" as named transient in cmd/container.go alongside existing "sh", "pwsh", "python"
• Update docs/language-hooks.md with JavaScript section (configuration examples, package manager detection, package.json handling)

Acceptance Criteria

• .js hook scripts auto-detected and executed via Node.js
• package.json discovered via walk-up, dependencies installed before execution
• Package manager auto-detected from lock files (package-lock.json → npm, pnpm-lock.yaml → pnpm, yarn.lock → yarn)
• Standalone .js scripts (no package.json) execute without dependency installation
• Missing Node.js → clear error with install URL via ErrorWithSuggestion
• Environment variables passed through to script process
• kind: js explicit override works in azure.yaml
• Existing shell and Python hooks unaffected (no regression)
• IoC registration as named transient "js" in container.go

Out of Scope

• TypeScript compilation/execution (separate issue)
• Deno or Bun runtime support
• Global npm package installation

Testing Expectations

• Unit tests for jsExecutor (Prepare, Execute, Cleanup) with mocked node.Cli and CommandRunner
• Unit tests for package manager detection from lock files
• E2E test: JS hook with package.json → npm install → execute → verify output
• E2E test: standalone JS script → execute without install
• E2E test: missing Node.js → error with suggestion
• E2E test: continueOnError: true behavior
• E2E test: service-level JS hooks

Constraints

• Must reuse existing node.Cli singleton — do not create a separate Node wrapper
• Follow the Python executor pattern for consistency (Prepare/Execute/Cleanup lifecycle)
• Inline JavaScript hooks are rejected (file-based only, consistent with Python)

Related Issues

• Parent Epic: Multi-Language Hook Support: Python, JavaScript, TypeScript, .NET #7435 — Multi-Language Hook Support
• Resolved by Phase 1: PR feat: add multi-language hook support (Phase 1 — Python) #7451 — provides framework, HookExecutor interface, project discovery