Upgrade to Next.js 16 with Turbopack

[Copilot]

Upgrades all dependencies to latest versions and enables Turbopack for faster builds.

Major Changes

• Next.js 15.1.7 → 16.0.1 with Turbopack enabled via --turbo flag
• ESLint 9.20.1 → 9.38.0 with migration to flat config format (eslint.config.mjs)
• TypeScript 5.7.3 → 5.9.3 with updated compiler options for Next.js 16

Configuration Updates

• Migrated .eslintrc to eslint.config.mjs (required by ESLint 9+)
• Updated tsconfig.json: moduleResolution: "bundler", jsx: "react-jsx"
• Updated scripts: replaced deprecated next lint command (removed in v16) with eslint directly
• Removed unnecessary @eslint/eslintrc dependency (not needed with flat config)
• Added GitHub Actions workflow for linting and type checking (since Next.js 16 no longer runs linting during build)

Other Dependencies

• @types/react: 19.0.8 → 19.2.2
• @types/node: 22.13.1 → 22.18.13
• prettier: 3.5.0 → 3.6.2
• autoprefixer: 10.4.20 → 10.4.21
• postcss: 8.5.2 → 8.5.6

CI/CD

A new GitHub Actions workflow (.github/workflows/lint.yml) has been added to run TypeScript type checking and linting on all pushes and pull requests to main, ensuring code quality checks continue to run automatically.

Example Usage

# Development with Turbopack
yarn dev

# Production build with Turbopack
yarn build

Both commands now use the --turbo flag to leverage Next.js's Rust-based bundler for improved performance.

Note

Next.js 16 works without a configuration file when no custom configuration is needed, so next.config.ts was not created.

Original prompt

Upgrade all dependencies. Upgrade to Next.js 16 with Turbopack. Make sure everything still builds and lints and typechecks.

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Project	Deployment	Preview	Comments	Updated (UTC)
cookbook	Ready	Preview	Comment	Oct 30, 2025 4:07am

[Copilot]

Pull Request Overview

This PR updates the project from Next.js 15 to Next.js 16, including major dependency updates and modernized configuration files. Key changes include upgrading to ESLint flat config format, enabling Turbopack mode, and updating TypeScript compiler settings for Next.js 16 compatibility.

• Upgraded Next.js from v15.1.7 to v16.0.1
• Migrated from legacy .eslintrc to modern eslint.config.mjs flat config
• Updated TypeScript configuration with Next.js 16 recommended settings

Reviewed Changes

Copilot reviewed 4 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
yarn.lock	Updated dependency versions including Next.js, ESLint, TypeScript, and numerous supporting packages
package.json	Updated scripts to use Turbo mode, bumped major dependencies (Next.js, ESLint, TypeScript)
tsconfig.json	Changed target to ES2020, moduleResolution to "bundler", jsx to "react-jsx", added path aliases
next.config.ts	Created new TypeScript configuration file for Next.js 16
next-env.d.ts	Added reference to routes type definitions
eslint.config.mjs	Created new ESLint flat config replacing .eslintrc
.eslintrc	Removed legacy ESLint configuration

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[Copilot]

Just as a heads up, I was blocked by some firewall rules while working on your feedback. Expand below for details.

[nwalters512]

@copilot since Next no longer runs linting during build, can you add a GitHub Actions workflow to run linting?

[Copilot]

@copilot since Next no longer runs linting during build, can you add a GitHub Actions workflow to run linting?

Added in ce7ad1c. The workflow runs TypeScript type checking and linting on all pushes and pull requests to main.