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package.json

{
  // 主要包入口定义
  "main": "lib/cjs/index.js",
  "unpkg": "dist/pkg.development.js",
  "types": "lib/types/index.d.ts",
  "esnext": "lib/esnext/index.d.ts",
  // 由 bundler 使用的 esm 入口
  "module": "lib/esm/index.js",
  // 导入单入口
  // "exports": "./index.js"
  // 导出多个入口
  // 未 export 的为私有
  // https://nodejs.org/api/esm.html#resolver-algorithm
  "exports": {
    // 定义后可自引用
    ".": "./main.mjs",
    // import {} from 'pkg/foo'
    "./foo": "./foo.js",

    // 同时支持 cjs 和 esm
    "import": "./index.mjs",
    "require": "./index.cjs",
    // typescript 4.7+
    // https://github.com/microsoft/TypeScript/issues/33079
    "types": "./index.ts",

    // 指定路径
    ".": {
      "types": "./lib/index.d.ts",
      "default": "./lib/index.js"
    },
    // 替代
    "./*": {
      "types": "./lib/*/index.d.ts",
      "default": "./lib/*/index.js"
    },
    // 允许访问
    "./package.json": "./package.json"
  },
  // Node 条件 resolve
  "node": "",
  "node-addons": "",
  "default": "",
  "import": "",
  "require": "",
  // 社区定义的条件
  "browser": "", // build for browser
  "deno": "", // build for deno

  "development": "", // dev build entrypoint - node --conditions=development main.js
  "production": "", // prod build entrypoint

  // 针对包的 import map
  "imports": {
    "#dep": {
      "node": "dep-node-native",
      "default": "./dep-polyfill.js"
    }
  },
  // 可以 tree shaking
  // /*#__PURE__*/
  "sideEffects": true,
  // 部分文件有 side effetcs
  "sideEffects": ["./src/register.js", "*.css", "!(dist/(components|utils)/**)"]
}
{
  "bundlewatch": {
    "files": [
      {
        "path": "dist/*.production.min.js"
      }
    ]
  }
}

exports​

  • TypeScript 4.7 支持 exports
  • TypeScript 5.0 支持 bundler moduleResolution
  • --conditions,-C
    • node --conditions=development index.js
    • 运行 node 指定 condition 会根据 condition resolve
  • 常见类型
    • types - d.ts - 一般放在最前面
    • import - esm - import,import() 使用 ECMAScript module loader
      • 可能 mjs 结尾
    • module
      • 可能 js 结尾
    • require - cjs
    • node - cjs/esm
    • node-addons - native C++ addons
    • default - cjs/esm - 优先级低
      • 注意
        • 一般为 esm
        • 一定要放在最后
        • 不建议，因为不用环境处理逻辑不同
  • 扩展
    • types - 优先级高
    • demo
    • browser - 例如 iife 格式
    • development
      • 有些为源码 - ts
      • 但是有些环境不支持 ts - 例如 nextjs
    • production
  • https://nodejs.org/api/packages.html#conditional-exports
package.json
{
  "sideEffects": "false",
  "types": "src/.ts",
  "main": "dist/cjs/index.js",
  "module": "lib/esm/index.mjs",
  "exports": {
    ".": {
      "types": "./src/index.ts",
      "import": "./lib/esm/index.mjs",
      "default": "./lib/cjs/index.js"
    },
    "./src/": "./src/",
    "./icons/*": "./lib/icons/*.json",
    "./package.json": "./package.json"
  }
}

exports types​

  • ts 4.7+
  • package.json - type module
  • tsconfig.json 的 module 设置为 Node12 或 NodeNext

替代方案

package.json
{
  "typesVersions": {
    "*": {
      "index": ["lib/components/index.d.ts"],
      "tokens": ["lib/tokens/index.d.ts"]
    }
  }
}

imports​

  • 包内映射 import
{
  "imports": {
    "#dep": {
      "node": "dep-node-native",
      "default": "./dep-polyfill.js"
    },
    "#internal/*.js": "./src/internal/*.js"
  },
  "dependencies": {
    "dep-node-native": "^1.0.0"
  }
}
// 根据环境 import dep-node-native 或 polyfill
import '#dep';

self-referencing​

Protocol​

  • link:
  • workspace:
    • 从 workspace 里选择
    • pnpm
  • pnp:
    • yarn plug & play
  • alias - <alias>@npm:<name>
  • lodash1@npm:lodash@1
  • git+{url}.git
  • <protocol>://[<user>[:<password>]@]<hostname>[:<port>][:][/]<path>[#<commit-ish> | #semver:<semver>]
    • GIT_ASKPASS
    • GIT_EXEC_PATH
    • GIT_PROXY_COMMAND
    • GIT_SSH
    • GIT_SSH_COMMAND
      • 例如修改 key GIT_SSH_COMMAND='ssh -i ~/.ssh/custom_ident'
    • GIT_SSL_CAINFO
    • GIT_SSL_NO_VERIFY
  • Github
    • <githubname>/<githubrepo>[#<commit-ish>]
    • github:<githubname>/<githubrepo>[#<commit-ish>]
  • Gist
    • gist:[<githubname>/]<gistID>[#<commit-ish>|#semver:<semver>]
  • bitbucket:<bitbucketname>/<bitbucketrepo>[#<commit-ish>]
  • gitlab:<gitlabname>/<gitlabrepo>[#<commit-ish>]
  • [<@scope>/]<name>@<tag>
  • 也可以 https://github.com/{USER}/{REPO}/tarball/{BRANCH}
caution
# support private
npm install git+ssh://[email protected]:user_name/node_project.git
npm install use_name/node_project#branch_name
npm install use_name/node_project#commit
npm i https://github.com/user_name/node_project_name
npm install gist/gist_id

resolve​

  • esm 要求有后缀
  • node 不要求
    • --experimental-specifier-resolution=node

engines​

{
  "engines": {
    "node": "^16 || ^18"
  }
}
npx -y check-engine