packages/reactivity/package.json

{
  // 模块的名称
  "name": "@vue/reactivity",
  "version": "1.0.0",
  // 打包后的文件名称和地址
  "module": "dist/reacticity.esm-bundler.js",
  "unpkg": "dist/reactivity.global.js",
  // 供打包时使用
  "buildOptions": {
    "name": "VueReactivity",
    "formats": [
      "esm-bundler",
      "esm-browser",
      "cjs",
      "global"
    ]
  },
}

packages/reactivity/src/reactive.ts

export function reactive() {
  
}

packages/reactivity/src/effect.ts

export function effect() {
  
}

packages/reactivity/src/index.ts

export * from './reactive'
export * from './effect'

packages/shared/package.json

{
  "name": "@vue/shared",
  "version": "1.0.0",
  "module": "dist/shared.esm-bundler.js",
  "buildOptions": {
    "formats": [
      "esm-bundler",
      "cjs"
    ]
  }
}

packages/shared/src/index.ts

export function isObject(value) {
  return typeof value === 'object' && value !== null;
}