Bun に入門する

$ bun --version
1.0.3

$ curl -fsSL https://bun.sh/install | bash

$ bun --help
	-h, --help                      	Display this help and exit.
	-b, --bun                       	Force a script or package to use Bun's runtime instead of Node.js (via symlinking node)
	    --cwd <STR>                 	Absolute path to resolve files & entry points from. This just changes the process' cwd.
	-c, --config <PATH>?            	Config file to load Bun from (e.g. -c bunfig.toml
	    --extension-order <STR>...  	Defaults to: .tsx,.ts,.jsx,.js,.json
	    --jsx-factory <STR>         	Changes the function called when compiling JSX elements using the classic JSX runtime
	    --jsx-fragment <STR>        	Changes the function called when compiling JSX fragments
	    --jsx-import-source <STR>   	Declares the module specifier to be used for importing the jsx and jsxs factory functions. Default: "react"
	    --jsx-runtime <STR>         	"automatic" (default) or "classic"
	-r, --preload <STR>...          	Import a module before other modules are loaded
	    --main-fields <STR>...      	Main fields to lookup in package.json. Defaults to --target dependent
	    --no-summary                	Don't print a summary (when generating .bun)
	-v, --version                   	Print version and exit
	    --revision                  	Print version with revision and exit
	    --tsconfig-override <STR>   	Load tsconfig from path instead of cwd/tsconfig.json
	-d, --define <STR>...           	Substitute K:V while parsing, e.g. --define process.env.NODE_ENV:"development". Values are parsed as JSON.
	-e, --external <STR>...         	Exclude module from transpilation (can use * wildcards). ex: -e react
	-l, --loader <STR>...           	Parse files with .ext:loader, e.g. --loader .js:jsx. Valid loaders: js, jsx, ts, tsx, json, toml, text, file, wasm, napi
	-u, --origin <STR>              	Rewrite import URLs to start with --origin. Default: ""
	-p, --port <STR>                	Port to serve Bun's dev server on. Default: "3000"
	    --smol                      	Use less memory, but run garbage collection more often
	    --minify                    	Minify (experimental)
	    --minify-syntax             	Minify syntax and inline data (experimental)
	    --minify-whitespace         	Minify whitespace (experimental)
	    --minify-identifiers        	Minify identifiers
	    --no-macros                 	Disable macros from being executed in the bundler, transpiler and runtime
	    --target <STR>              	The intended execution environment for the bundle. "browser", "bun" or "node"
	    --inspect <STR>?            	Activate Bun's Debugger
	    --inspect-wait <STR>?       	Activate Bun's Debugger, wait for a connection before executing
	    --inspect-brk <STR>?        	Activate Bun's Debugger, set breakpoint on first line of code and wait
	    --hot                       	Enable auto reload in the Bun runtime, test runner, or bundler
	    --watch                     	Automatically restart the process on file change
	    --no-install                	Disable auto install in the Bun runtime
	-i                              	Automatically install dependencies and use global cache in Bun's runtime, equivalent to --install=fallback
	    --install <STR>             	Install dependencies automatically when no node_modules are present, default: "auto". "force" to ignore node_modules, fallback to install any missing
	    --prefer-offline            	Skip staleness checks for packages in the Bun runtime and resolve from disk
	    --prefer-latest             	Use the latest matching versions of packages in the Bun runtime, always checking npm
	    --silent                    	Don't repeat the command for bun run
	    --dump-environment-variables	Dump environment variables from .env and process as JSON and quit. Useful for debugging
	    --dump-limits               	Dump system limits. Useful for debugging

-------

Bun: a fast JavaScript runtime, package manager, bundler and test runner. (1.0.3)

  run       ./my-script.ts       Run JavaScript with Bun, a package.json script, or a bin
  test                           Run unit tests with Bun
  x         prettier             Install and execute a package bin (bunx)
  repl                           Start a REPL session with Bun

  init                           Start an empty Bun project from a blank template
  create    elysia               Create a new project from a template (bun c)

  install                        Install dependencies for a package.json (bun i)
  add       zod                  Add a dependency to package.json (bun a)
  remove    backbone             Remove a dependency from package.json (bun rm)
  update    tailwindcss          Update outdated dependencies
  link                           Link an npm package globally
  unlink                         Globally unlink an npm package
  pm                             More commands for managing packages

  build     ./a.ts ./b.jsx       Bundle TypeScript & JavaScript into a single file

  upgrade                        Get the latest version of Bun
  bun --help                     Show all supported flags and commands

  Learn more about Bun:          https://bun.sh/docs
  Join our Discord community:    https://bun.sh/discord

➜ bun repl
Welcome to Bun v1.0.3
Type ".help" for more information.
[!] Please note that the REPL implementation is still experimental!
    Don't consider it to be representative of the stability or behavior of Bun overall.
> const x = 'hello'
undefined
> console.log(x)
hello
undefined
> const x = 'hello2'
SyntaxError: Can't create duplicate variable: 'x'

> const y: string = 'hello'
undefined
> const z: string = 10
undefined

type Main = () => Promise<void>

const main: Main = async () => {
  console.log('hello! from bun')
}

main()
  .then(() => {
    console.log('successfully completed!')
  })
  .catch((err) => {
    console.error(err)
  })

$ bun run ./sample.ts
hello! from bun
successfully completed!

type Main = () => Promise<string>

const main: Main = async () => {
  console.log('hello! from bun')
}

main()
  .then(() => {
    console.log('successfully completed!')
  })
  .catch((err) => {
    console.error(err)
  })

$ bun run ./sample.ts
hello! from bun
successfully completed!

import { readFileSync } from 'node:fs'

type Main = () => Promise<void>

const main: Main = async () => {
  const content = readFileSync('./sample.ts', { encoding: 'utf8' })
  console.log('hello! from bun', content)
}

main()
  .then(() => {
    console.log('successfully completed!')
  })
  .catch((err) => {
    console.error(err)
  })

$ bun run ./sample.ts
hello! from bun import { readFileSync } from 'node:fs'

type Main = () => Promise<void>

const main: Main = async () => {
  const content = readFileSync('./sample.ts', { encoding: 'utf8' })
  console.log('hello! from bun', content)
}

main()
  .then(() => {
    console.log('successfully completed!')
  })
  .catch((err) => {
    console.error(err)
  })

successfully completed!

$ bun init
bun init helps you get started with a minimal project and tries to guess sensible defaults. Press ^C anytime to quit

package name (bun-playground): 
entry point (index.ts): src/index.ts

Done! A package.json file was saved in the current directory.
 + src/index.ts
 + .gitignore
 + tsconfig.json (for editor auto-complete)
 + README.md

To get started, run:
  bun run src/index.ts

{
  "compilerOptions": {
    "lib": ["ESNext"],
    "module": "esnext",
    "target": "esnext",
    "moduleResolution": "bundler",
    "moduleDetection": "force",
    "allowImportingTsExtensions": true,
    "noEmit": true,
    "composite": true,
    "strict": true,
    "downlevelIteration": true,
    "skipLibCheck": true,
    "jsx": "react-jsx",
    "allowSyntheticDefaultImports": true,
    "forceConsistentCasingInFileNames": true,
    "allowJs": true,
    "types": [
      "bun-types" // add Bun global
    ]
  }
}

$ bun add -D typescript
bun add v1.0.3 (25e69c71)

 installed typescript@5.2.2 with binaries:
  - tsc
  - tsserver


 1 packages installed [97.00ms

{
  "name": "sample",
  "module": "index.ts",
  "main": "dist/index.js",
  "type": "module",
  "scripts": {
    "build": "run-s 'build:*'",
    "build:bundle": "bun bun ./index.ts --outdir dist",
    "build:types": "tsc"
  },
  "devDependencies": {
    "bun-types": "latest",
    "npm-run-all": "^4.1.5",
    "typescript": "^5.2.2"
  },
  "peerDependencies": {
    "typescript": "^5.0.0"
  }
}

{
  "compilerOptions": {
    "lib": ["ESNext"],
    "module": "esnext",
    "target": "esnext",
    "moduleResolution": "bundler",
    "moduleDetection": "force",
    "allowImportingTsExtensions": true,
    "composite": true,
    "strict": true,
    "downlevelIteration": true,
    "skipLibCheck": true,
    "jsx": "react-jsx",
    "allowSyntheticDefaultImports": true,
    "forceConsistentCasingInFileNames": true,
    "allowJs": true,
    "types": [
      "bun-types" // add Bun global
    ],
    // added
    "outDir": "dist",
    "noEmit": false,
    "emitDeclarationOnly": true
  }
}

{
  "name": "bun-playground",
  "module": "src/index.ts",
  "type": "module",
  "workspaces": [
    "packages/*"
  ],
  "dependencies": {
    "sample": "workspace:*"
  },
  "devDependencies": {
    "bun-types": "latest",
    "typescript": "^5.2.2"
  },
  "peerDependencies": {
    "typescript": "^5.0.0"
  }
}

import { valueInSampleApp } from 'sample'

type Main = () => Promise<void>

const main: Main = async () => {
  console.log('hello! from bun', valueInSampleApp)
}

main()
  .then(() => {
    console.log('successfully completed!')
  })
  .catch((err) => {
    console.error(err)
  })

$ bun --cwd ./packages/sample run build
sample scripts:

 bun run build
   run-s 'build:*'

 bun run build:bundle
   bun bun ./index.ts --outdir dist

 bun run build:types
   tsc

3 scripts

$ bun run ./sample.ts 
hello! from bun valueInSampleApp
successfully completed!

$ bun build ./src/main.ts --outdir ./out --target bun --external class-transformer/storage