@contractkit/prettier-plugin

A Prettier plugin that formats ContractKit .ck files. Idempotent: re-formatting an already-formatted file is a no-op.

Installation

pnpm add -D prettier @contractkit/prettier-plugin

Configuration

Add the plugin to your prettier config:

{
    "plugins": ["@contractkit/prettier-plugin"]
}

Prettier registers .ck as the ContractDSL language and applies the plugin automatically.

Usage

# Format all .ck files in your project
pnpm prettier --write "**/*.ck"

# Or via the editor integration of your choice

Most editors with a Prettier integration (VS Code, JetBrains, Neovim) pick the plugin up from your project's package.json automatically.

What it does

The printer round-trips the parser's AST back into canonical .ck source:

• 4-space indentation (matches Prettier's default tabWidth)
• Canonical modifier order on fields: override → deprecated → readonly|writeonly
• Stable ordering of options block items, route bodies, and operation blocks
• Inline # comment placement preserved on field/operation/status lines
• Multi-base inheritance: contract C: A & B & { ... } with the inline block always last
• Multi-line unions: a leading | is preserved on type aliases like contract X: A | B | C
• Discriminated unions render as discriminated(by=field, A | B | C)
• Options-level header globals (options { request/response: { headers } }) are emitted in their original un-merged form so the AST round-trips cleanly

The plugin honours Prettier's printWidth for line-wrapping decisions where applicable, but most CK constructs format to a fixed multi-line shape regardless of width.

Source layout

| Path | Purpose | | --- | --- | | src/index.ts | Prettier plugin entry — parser + printer registration | | src/print-ck.ts | Top-level dispatcher; renders the options { ... } block | | src/print-contract.ts | Renders contract declarations and field blocks | | src/print-operation.ts | Renders operation declarations, params, query, headers, request/response | | src/print-type.ts | Shared type-expression printer used everywhere a type appears | | src/indent.ts | Indentation constants and helpers |