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Watch Mode

Tweaking colours one build at a time gets old fast. Watch mode rebuilds your theme automatically whenever you save.

Start Watching​

TERMINAL
npx @gesslar/sassy build ocean.yaml --watch

Sassy monitors your theme file (and any imported files) for changes. Save ocean.yaml and the output regenerates instantly.

Smart Output​

Sassy computes a SHA-256 hash of the output before writing. If nothing actually changed — say you saved without editing — it skips the write entirely. This avoids triggering unnecessary VS Code reloads when you're working with auto-reload extensions.

Useful Flags​

--output-dir — Write the compiled theme to a specific directory instead of alongside the source file. Handy for writing directly into your VS Code extensions folder:

TERMINAL
npx @gesslar/sassy build ocean.yaml --watch --output-dir ~/.vscode/extensions/ocean-theme/

--dry-run — Process the theme and report results without writing any files. Useful for validating your theme before committing changes.

TERMINAL
npx @gesslar/sassy build ocean.yaml --dry-run

What You've Learned​

Over these seven pages, you've built a complete VS Code dark theme using Sassy. Here's what you covered:

  1. Theme structure — config, vars, and theme sections
  2. Variables — named values with dot-path nesting
  3. Colour palette — raw colours and semantic aliases
  4. Colour functions — lighten(), darken(), fade(), mix() for derived colours
  5. Token colours — syntax highlighting with TextMate scopes
  6. UI styling — status colours, panels, inputs, and activity bar
  7. Watch mode — live rebuilds for rapid iteration

Next Steps​

The Quick Start covered the fundamentals. There's more to explore:

  • Imports — split large themes across multiple files
  • Multiple themes — share a palette between light and dark variants
  • Advanced colour functions — the full set of Culori-powered transformations
  • Linting — catch duplicate scopes, undefined variables, and precedence issues

Head to the Diving Deeper section to keep going.