个人理解package.json是npm包项目配置文件， 而npm是node的包管理工具

1. package.json文件初始化

npm init

2. package.json文件字段详解

package.json必须含有name和version字段

{
    //包名称
    "name":"vue3-plain",
    //项目包版本
    "version": "1.0.0",
    //包信息描述
    "description": "学习vue3源码",
    //作者信息
    "author": "",
    //是否私有包
    "private": true,
    //许可证
    "license": "ISC",
    //关键字
    "keywords": ["vue3"],
    //项目启动入口文件
    "main": "index.js",
    //包脚本
    "scripts": {
        "dev": "node scripts/dev.js",
        "build": "node scripts/build.js"
    },
    //项目包资源库
    "repository":"",
    //项目运行依赖
    "dependencies":{
    },
    //项目运行依赖
    "devDependencies": {
        "@babel/types": "^7.18.7",
        "@rollup/plugin-commonjs": "^22.0.0",
        "@rollup/plugin-json": "^4.1.0",
        "@rollup/plugin-node-resolve": "^13.3.0",
        "@rollup/plugin-replace": "^4.0.0",
        "@types/jest": "^28.1.6",
        "@types/node": "^18.0.1",
        "chalk": "^5.0.1",
        "esbuild": "^0.14.41",
        "execa": "^6.1.0",
        "fs-extra": "^10.1.0",
        "minimist": "^1.2.6",
        "rollup": "^2.75.3",
        "rollup-plugin-typescript2": "^0.31.2",
        "typescript": "^4.7.2"
    },
    //预依赖
    "peerDependencies":{
    },
    //包项目依赖安装时包含的文件条目
    "files":[],
    //用于告知要支持那些浏览器及版本
    "browserslist": ["> 1%", "last 2 versions", "not ie <= 8"],
    //声明该项目模块运行的平台及版本
    "engines":["node":">=16.13.0"]
}