一：package.json文件详解
管理你本地安装的npm包 。定义了这个项目所需要的各种模块，以及项目的配置信息（比如名称、版本、许可证等元数据）。npm install命令根据这个配置文件，自动下载所需的模块，也就是配置项目所需的运行和开发环境。
{
"name": "vue2-manage",
"version": "1.0.1",
"description": "vue2-manage",
"author": "cangdu <1264889788@qq.com>",
"license": "GPL",
"private": true,
"scripts": {
"dev": "cross-env NODE_ENV=online node build/dev-server.js",
"local": "cross-env NODE_ENV=local node build/dev-server.js",
"build": "node build/build.js",
"unit": "cross-env BABEL_ENV=test karma start test/unit/karma.conf.js --single-run",
"e2e": "node test/e2e/runner.js",
"test": "npm run unit && npm run e2e",
"lint": "eslint --ext .js,.vue src test/unit/specs test/e2e/specs"
},
"dependencies": {
"echarts": "^3.5.4",
"element-ui": "^1.2.9",
"time-formater": "^1.0.1",
"vue": "^2.2.6",
"vue-quill-editor": "^2.2.1",
"vue-router": "^2.3.1",
"vue-simplemde": "^0.3.8",
"vuex": "^2.3.1"
},
"devDependencies": {
"autoprefixer": "^6.7.2",
"babel-core": "^6.22.1",
"babel-eslint": "^7.1.1",
"babel-loader": "^6.2.10",
"babel-plugin-component": "^0.9.1",
"babel-plugin-istanbul": "^4.1.1",
"babel-plugin-transform-runtime": "^6.22.0",
"babel-polyfill": "^6.23.0",
"babel-preset-env": "^1.3.2",
"babel-preset-stage-2": "^6.22.0",
"babel-register": "^6.22.0",
"babel-runtime": "^6.23.0",
"chai": "^3.5.0",
"chalk": "^1.1.3",
"chromedriver": "^2.27.2",
"connect-history-api-fallback": "^1.3.0",
"copy-webpack-plugin": "^4.0.1",
"cross-env": "^4.0.0",
"cross-spawn": "^5.0.1",
"css-loader": "^0.28.0",
"eslint": "^3.19.0",
"eslint-config-standard": "^6.2.1",
"eslint-friendly-formatter": "^2.0.7",
"eslint-loader": "^1.7.1",
"eslint-plugin-html": "^2.0.0",
"eslint-plugin-promise": "^3.4.0",
"eslint-plugin-standard": "^2.0.1",
"eventsource-polyfill": "^0.9.6",
"express": "^4.14.1",
"extract-text-webpack-plugin": "^2.0.0",
"file-loader": "^0.11.1",
"friendly-errors-webpack-plugin": "^1.1.3",
"html-webpack-plugin": "^2.28.0",
"http-proxy-middleware": "^0.17.3",
"inject-loader": "^3.0.0",
"karma": "^1.4.1",
"karma-coverage": "^1.1.1",
"karma-mocha": "^1.3.0",
"karma-phantomjs-launcher": "^1.0.2",
"karma-phantomjs-shim": "^1.4.0",
"karma-sinon-chai": "^1.3.1",
"karma-sourcemap-loader": "^0.3.7",
"karma-spec-reporter": "0.0.30",
"karma-webpack": "^2.0.2",
"less": "^2.7.2",
"less-loader": "^4.0.3",
"lolex": "^1.5.2",
"mocha": "^3.2.0",
"nightwatch": "^0.9.12",
"opn": "^4.0.2",
"optimize-css-assets-webpack-plugin": "^1.3.0",
"ora": "^1.2.0",
"phantomjs-prebuilt": "^2.1.14",
"rimraf": "^2.6.0",
"selenium-server": "^3.0.1",
"semver": "^5.3.0",
"shelljs": "^0.7.6",
"sinon": "^2.1.0",
"sinon-chai": "^2.8.0",
"url-loader": "^0.5.8",
"vue-loader": "^11.3.4",
"vue-style-loader": "^2.0.5",
"vue-template-compiler": "^2.2.6",
"webpack": "^2.3.3",
"webpack-bundle-analyzer": "^2.2.1",
"webpack-dev-middleware": "^1.10.0",
"webpack-hot-middleware": "^2.18.0",
"webpack-merge": "^4.1.0"
},
"engines": {
"node": ">= 4.0.0",
"npm": ">= 3.0.0"
},
"browserslist": [
"> 1%",
"last 2 versions",
"not ie <= 8"
]
}
scripts字段:
指定了运行脚本命令的npm命令行缩写;
比如： dev : "dev": "cross-env NODE_ENV=online node build/dev-server.js"
dependencies字段:
指定了项目运行所依赖的模块.
devDependencies字段：
指定项目开发所需要的模块。
engines字段：
指明了该模块运行的平台，比如 Node 的某个版本或者浏览器。
2 package.json文件生成
package.json文件可以手工编写，也可以使用npm init命令自动生成；
这个命令采用互动方式，要求用户回答一些问题，然后在当前目录生成一个基本的package.json文件。所有问题之中，只有项目名称（name）和项目版本（version）是必填的，其他都是选填的。
有了package.json文件，直接使用npm install命令，就会在当前目录中安装所需要的模块。
3 package.json是给nodejs用的, 还是npm
npm在package.json文件中管理项目的依赖项以及项目的元数据。
node执行js中require的时候，也会根据package.json中的依赖项查找。
来源：https://www.cnblogs.com/liufei1983/p/8745749.html