bun macros

仓库: secondsky/claude-skills
安装量: 51
排名: #14613

安装

npx skills add https://github.com/secondsky/claude-skills --skill 'Bun Macros'

Bun Macros Bun macros run JavaScript at bundle time and inline the results into the output. Quick Start // src/config.ts (macro file) export function getVersion ( ) { return "1.0.0" ; } export function getBuildTime ( ) { return new Date ( ) . toISOString ( ) ; } // src/index.ts (consumer) import { getVersion , getBuildTime } from "./config" with { type : "macro" } ; // At bundle time, these become: const version = "1.0.0" ; const buildTime = "2024-01-15T12:00:00.000Z" ; Macro Syntax // Import with macro attribute import { fn } from "./macro-file" with { type : "macro" } ; // Call the macro (evaluated at build time) const result = fn ( ) ; Common Use Cases Environment Inlining // macros/env.ts export function env ( key : string ) : string { return process . env [ key ] ?? "" ; } // src/index.ts import { env } from "./macros/env" with { type : "macro" } ; const apiUrl = env ( "API_URL" ) ; // Becomes: const apiUrl = "https://api.example.com"; Git Information // macros/git.ts export function gitCommit ( ) : string { return Bun . spawnSync ( [ "git" , "rev-parse" , "HEAD" ] ) . stdout . toString ( ) . trim ( ) ; } export function gitBranch ( ) : string { return Bun . spawnSync ( [ "git" , "branch" , "--show-current" ] ) . stdout . toString ( ) . trim ( ) ; } // src/index.ts import { gitCommit , gitBranch } from "./macros/git" with { type : "macro" } ; const BUILD_INFO = { commit : gitCommit ( ) , branch : gitBranch ( ) , } ; // Inlined at build time File Embedding // macros/embed.ts export function embedFile ( path : string ) : string { return Bun . file ( path ) . text ( ) ; } export function embedJSON ( path : string ) : unknown { return Bun . file ( path ) . json ( ) ; } // src/index.ts import { embedFile , embedJSON } from "./macros/embed" with { type : "macro" } ; const license = embedFile ( "./LICENSE" ) ; const config = embedJSON ( "./config.json" ) ; Build Constants // macros/constants.ts export function isDev ( ) : boolean { return process . env . NODE_ENV !== "production" ; } export function buildDate ( ) : number { return Date . now ( ) ; } export function randomId ( ) : string { return Math . random ( ) . toString ( 36 ) . slice ( 2 ) ; } // src/index.ts import { isDev , buildDate , randomId } from "./macros/constants" with { type : "macro" } ; if ( isDev ( ) ) { console . log ( "Development mode" ) ; } const BUILD_ID = randomId ( ) ; Directory Listing // macros/files.ts import { readdirSync } from "fs" ; export function listRoutes ( ) : string [ ] { return readdirSync ( "./src/routes" ) . filter ( f => f . endsWith ( ".tsx" ) ) . map ( f => f . replace ( ".tsx" , "" ) ) ; } // src/router.ts import { listRoutes } from "./macros/files" with { type : "macro" } ; const routes = listRoutes ( ) ; // Becomes: const routes = ["home", "about", "users"]; Code Generation // macros/codegen.ts export function generateTypes ( schema : string ) : string { // Parse schema and generate types at build time const types = parseSchemaToTypes ( schema ) ; return types ; } export function generateAPI ( spec : string ) : string { const openapi = JSON . parse ( Bun . file ( spec ) . text ( ) ) ; // Generate API client code return generateClientFromOpenAPI ( openapi ) ; } Return Types Macros can return: // Primitives export function getString ( ) : string { return "hello" ; } export function getNumber ( ) : number { return 42 ; } export function getBoolean ( ) : boolean { return true ; } export function getNull ( ) : null { return null ; } // Objects (serializable) export function getObject ( ) : object { return { key : "value" , nested : { a : 1 } } ; } // Arrays export function getArray ( ) : string [ ] { return [ "a" , "b" , "c" ] ; } // Response (for bundler plugins) export function getResponse ( ) : Response { return new Response ( "content" , { headers : { "Content-Type" : "text/plain" } , } ) ; } Async Macros // macros/fetch.ts export async function fetchSchema ( ) : Promise < object

{ const response = await fetch ( "https://api.example.com/schema.json" ) ; return response . json ( ) ; } // src/index.ts import { fetchSchema } from "./macros/fetch" with { type : "macro" } ; const schema = await fetchSchema ( ) ; // Fetched at build time, inlined as object literal Parameters // macros/parameterized.ts export function repeat ( str : string , count : number ) : string { return str . repeat ( count ) ; } export function formatDate ( format : string ) : string { return new Date ( ) . toLocaleDateString ( "en-US" , { dateStyle : format as any , } ) ; } // src/index.ts import { repeat , formatDate } from "./macros/parameterized" with { type : "macro" } ; const separator = repeat ( "-" , 20 ) ; const date = formatDate ( "long" ) ; Conditional Code // macros/platform.ts export function platform ( ) : "node" | "bun" | "browser" { if ( typeof Bun !== "undefined" ) return "bun" ; if ( typeof process !== "undefined" ) return "node" ; return "browser" ; } // src/index.ts import { platform } from "./macros/platform" with { type : "macro" } ; if ( platform ( ) === "bun" ) { // This block is kept or removed at build time console . log ( "Running on Bun" ) ; } Bundle-Only Execution Macros ONLY run during bundling:

Macros executed

bun build src/index.ts --outdir = dist

Macros NOT executed (runtime)

bun run src/index.ts Error Handling // macros/safe.ts export function requireEnv ( key : string ) : string { const value = process . env [ key ] ; if ( ! value ) { throw new Error ( Missing required env var: ${ key } ) ; } return value ; } // Build fails if env var missing import { requireEnv } from "./macros/safe" with { type : "macro" } ; const secret = requireEnv ( "API_SECRET" ) ; Debugging Macros // macros/debug.ts export function debug ( label : string , value : unknown ) : unknown { console . log ( [MACRO] ${ label } : , value ) ; return value ; } // See output during build bun build src / index . ts -- outdir = dist // [MACRO] config: { ... } Best Practices Keep macros pure - Avoid side effects Return serializable values - Must be JSON-compatible Handle errors - Throw meaningful errors for build failures Document dependencies - Note what files/env vars are required Test separately - Macros can be tested as regular functions Common Errors Error Cause Fix Cannot find module Wrong import path Check macro file location Not serializable Function/class returned Return plain data Macro failed Runtime error in macro Debug macro separately Not evaluated Missing with { type: "macro" } Add import attribute When to Load References Load references/advanced-patterns.md when: Complex code generation Plugin integration Build pipelines Retrieve and present patterns for custom macro implementations, integration examples with build systems, and advanced bundler plugin workflows. Load references/debugging.md when: Macro not evaluating Unexpected output Performance issues Retrieve debugging techniques, provide step-by-step diagnostics, and offer optimization strategies tied to the user's specific issue.

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