文檔： package.jsonnpmCLI（和yarn）用它來識(shí)別你的項(xiàng)目并了解如何處理項(xiàng)目的依賴關(guān)系。package.json文件使npm可以啟動(dòng)你的項(xiàng)目、運(yùn)行、安裝依賴項(xiàng)、發(fā)布到NPM表以及許多其他有用的任務(wù)。package字mkdirmkdirpackage-learn&&cdpackage-npmnpminit-}}"name":"package-"version":"description":"scripts":{"test":"echo\"Error:notestspecified\"&&exit ":"author":"license":{碼。npm是用npm-semver來解析版本號(hào)的npm模塊的完整的版本號(hào)一般是【小版本"devDependencies":"devDependencies":"@testing-library/jest-dom":"^4.2.0","@testing-library/react":"^9.3.0","alex":"^8.0.0","eslint":"execa":"fs-extra":"get-port":"globby":"husky":"jest":"lerna":"lerna-changelog":"lint-staged":"meow":"multimatch":"prettier":"puppeteer":"strip-ansi":"svg-term-cli":"tempy":"wait-for-localhost":大版本不變：比如"meow":"^5.0.0"：大版本不能變，如果大版本為0， "description":"description":"CreateReactappswithnobuild""":}"main":{"license":"license":"ISC""license":"MIT"證證 作為證，或者設(shè)置{"private":true}阮一峰老師：http://w author和contributors字段的功能類似。它們都是people字段，可以是"Name"格式的字符串，也可以是具有name， ，url字段 和url都是可選的。 "author":""contributors":"author":""contributors":[{"name":"lao ": dependencies&&存放用于本地開發(fā)的，dependencies會(huì)在我們開發(fā)的時(shí)候帶到線上。npmixxx-npmixxx-

npmixxx-

{"dependencies""foo"1.0.02.9999.9999"bar":">=1.0.2"baz":">1.0.2"boo"2.0.1"qux":"<1.0.0||>=2.3.1<2.4.5||>=2.5.2"asd /asdf.tar.gz"til"~1.2","elf":"elf"^1.2.3"two"2.x"2.1、2.2、...、2.9皆可用"thr":"*",//任意版本"thr2""lat"latest"dyl"file:../dyl"xyz": :npm/npm.git#v1.0.27",git"fir":"git+ss "wdy":"git+https:/ "xxy":" }{{"version":"0.0.1","peerDependencies":{ ck":}{"production":"not"notop_mini"development":"last1chromeversion","last1firefoxversion","last1safariversion"]}npm npm{{}"engines":"engines":"node":"npm":">="files":"files":]{"type":"git","url":"git+npmCLI用來運(yùn)行項(xiàng)目任務(wù)的強(qiáng)大工具。他們可以完成開發(fā)過程中的大"scripts":"build":"cdpackages/react-scripts&&nodebin/react-scripts.jsbuild","changelog":"lerna-"create-react-app":"nodetasks/cra.js","e2e":"tasks/e2e-simple.sh","e2e:docker":"tasks/local-test.sh","postinstall":"cdpackages/react-error-overlay/&&yarn"publish":"start":"cdpackages/react-scripts&&nodebin/react-scripts.jsstart","test":"cdpackages/react-scripts&&nodebin/react-scripts.jstest","format":"prettier maes5--single-quote--write'packages/*/*.js''packages/*/!(node_modules)/**/*.js'","dev":"rimraf\"config/.conf.json\"&&}}"clean":"rimraf./dist&&mkdirdist","prebuild":"npmrunclean","build:test":"cross-envNODE_ENV=productionnpm的原理非常簡(jiǎn)單。每當(dāng)執(zhí)行npmrun，就會(huì)自動(dòng)新建一個(gè)S 在這個(gè)S 里面執(zhí)行指定的命令。因此，只要是S （一般是Bash）可以運(yùn)行令，就可以寫在npm里面。我們最常用的npmstart，npmrundev……，這些都是可以用戶自定義 "scripts":"scripts":"build":ck--config"start":"node"test":"tap}比較特別的是，npmrun新建的這個(gè)S "scripts":"scripts":{"test":"tap"scripts":"scripts":{"test":"node_modules/.bin/tapnpmcross-=,數(shù)Windows命令提示將會(huì)阻塞(報(bào)錯(cuò))。（異常是Windows上的Bash，它使使用POSIX，您可以使用：$ENV_VAR和使用％ENV_VAR％的Windows說npminstall--save-devcross-{"scripts":"build":"cross-envNODE_ENV=productionck-- }}* *"lint":"jshint*.js""lint":"lint":"jshint*.js""lint":"jshint**/*.js" "test":"test":"tap"server":"server":iframe=trueck-dev-server--mode=development--open- $$npmrunscript1.js&npmrun$$npmrunscript1.js&&npmrunnpm有pre和post兩個(gè)鉤子，前者是在運(yùn)行前，后者是在運(yùn)行后執(zhí)行,所有令都可以使用鉤子（包括自定義的）。例如：運(yùn)行npmrunbuildnpmrunprebuild-->npmrunbuild-->npmrun"clean":"clean":"rimraf./dist&&mkdirdist","prebuild":"npmclean","build":"cross-envNODE_ENV=production "clean":"rimraf./dist&&mkdirdist","prebuild":"npmrunclean","build":"cross-envNODE_ENV=productionpretest，posttestprestop，"clean":"rimraf本地搭建一個(gè)HTTP"serve":"http-server-p9090打開瀏覽"open:dev":"livereload":"live-reload--port9091構(gòu)建HTML"build:html":"jadeindex.jade>只要CSS"watch:css":"watch'npmrunbuild:css'只要HTML"watch:html":"watch'npmrunbuild:html'構(gòu)建"build:favicon":"build:favicon":"nodenpm有一個(gè)非常強(qiáng)大的功能，就是可以使用npm的內(nèi)部變量首先，通過npm_package_前綴，npm可以拿到package.json里面的字////{"name":"scripts":{"view":"node}}console.log(process.env.npm_package_name);//fooconsole.log(process.env.npm_package_version);console.log(process.env.npm_package_name);//fooconsole.log(process.env.npm_package_version);//1.2.5地安裝我們可以在當(dāng)前工程令行中執(zhí)行該文件。"bin":"bin":"create-react-app":}要注意：這個(gè)index.js文件的頭部必須有這個(gè) 點(diǎn)，否則將在沒有節(jié)點(diǎn)可執(zhí)行文件的情況下啟動(dòng)。通過npminit-y創(chuàng)建一個(gè)package.json{{"name":"test-"version":"description":"bin":{"kkb":"scripts": ":"author":"license":"ISC",} #!/usr/bin/envnode#!/usr/bin/envnodemac,window下：npm gitnpmCLI和lerna用于管理多package，且