Yarn简介
Yarn 是 Facebook, Google, Exponent 和 Tilde 开发的一款新的 JavaScript 包管理工具。就像我们可以从官方文档了解那样，它的目的是解决这些团队使用 npm 面临的少数问题.
一键安装
官网脚本:
curl -o- -L https://yarnpkg.com/install.sh | bash -s -- --nightly
或者:
最简单的方法是运行：
npm install -g yarn
现在的yarn安装页面是这么说的：
注意：通常情况下不建议通过npm进行安装。npm安装是非确定性的，程序包没有签名，并且npm除了做了基本的SHA1哈希之外不执行任何完整性检查，这给安装系统程序带来了安全风险。
基于这些原因，强烈建议你通过最适合于你的操作系统的安装方法来安装yarn。
以这种速度发展下去的话，如果yarn要宣布他们自己的registry，让开发者慢慢淘汰npm的话，我们一点都不会感到惊讶。
安装成功后即可查看版本：
yarn –version
常用命令
初始化一个新项目
yarn init
添加依赖包
yarn add [package]
yarn add [package]@[version]
yarn add [package]@[tag]
将依赖项添加到不同依赖项类别中
分别添加到 devDependencies、peerDependencies 和 optionalDependencies 类别中：
yarn add [package] --dev
yarn add [package] --peer
yarn add [package] --optional
升级依赖包
yarn upgrade [package]
yarn upgrade [package]@[version]
yarn upgrade [package]@[tag]
移除依赖包
yarn remove [package]
安装项目的全部依赖
yarn
或者
yarn install
例如:
$ yarn install
yarn install v1.13.0-20181121.1436
warning package-lock.json found. Your project contains lock files generated by tools other than Yarn. It is advised not to mix package managers in order to avoid resolution inconsistencies caused by unsynchronized lock files. To clear this warning, remove package-lock.json.
[1/4] 🔍 Resolving packages...
[2/4] 🚚 Fetching packages...
[3/4] 🔗 Linking dependencies...
warning " > babel-jest@23.6.0" has unmet peer dependency "babel-core@^6.0.0 || ^7.0.0-0".
[4/4] 📃 Building fresh packages...
$ lerna bootstrap
lerna notice cli v3.4.3
lerna info Bootstrapping 5 packages
lerna info Installing external dependencies
lerna info Symlinking packages and binaries
lerna success Bootstrapped 5 packages
✨ Done in 271.39s.
$ yarn build
yarn run v1.13.0-20181121.1436
$ lerna run build --ignore selenium-ide-extension-boilerplate
lerna notice cli v3.4.3
lerna info filter [ '!selenium-ide-extension-boilerplate' ]
lerna info Executing command in 4 packages: "yarn run build"
$ yarn run browserify src/index.js -s browser-webdriver -o build/webdriver.js
$ /Users/jack/ui/selenium-ide/packages/browser-webdriver/node_modules/.bin/browserify src/index.js -s browser-webdriver -o build/webdriver.js
$ rollup -c
$ babel -d dist src --ignore=__test__
src/capabilities.js -> dist/capabilities.js
src/child.js -> dist/child.js
src/config.js -> dist/config.js
src/index.js -> dist/index.js
src/npm.js -> dist/npm.js
src/versioner.js -> dist/versioner.js
$ rm -rf build && env NODE_ENV=production webpack
Hash: 5f687715a247631dc1c4
Version: webpack 3.12.0
Time: 108660ms
Asset Size Chunks Chunk Names
escape.js.map 14.2 kB 6 [emitted] escape
media/selenium_blue_white32@3x.84ab23d0.svg 3.62 kB [emitted]
media/selenium-ide.9b39b00c.svg 21.8 kB [emitted]
playback.js 99.7 kB 0 [emitted] playback
record.js 39.4 kB 1 [emitted] record
neo.js 2.43 MB 2 [emitted] [big] neo
atoms.js 494 kB 3 [emitted] [big] atoms
background.js 12 kB 4 [emitted] background
polyfills.js 7.15 kB 5 [emitted] polyfills
escape.js 2.99 kB 6 [emitted] escape
playback.js.map 387 kB 0 [emitted] playback
record.js.map 162 kB 1 [emitted] record
neo.js.map 8.53 MB 2 [emitted] neo
atoms.js.map 2.23 MB 3 [emitted] atoms
background.js.map 54.8 kB 4 [emitted] background
polyfills.js.map 40.6 kB 5 [emitted] polyfills
media/selenium-ide.461193c2.ttf 7.44 kB [emitted]
vendor/global.js 825 bytes [emitted]
vendor/selenium-browserdetect.js 5.27 kB [emitted]
prompt.js 7.25 kB [emitted]
highlight.css 952 bytes [emitted]
../bootstrap.html 1.57 kB [emitted]
../manifest.json 1.74 kB [emitted]
indicator.js 694 bytes [emitted]
../indicator.html 1.03 kB [emitted]
../icons/icon128.png 5.88 kB [emitted]
../icons/icon_menu32.png 1.22 kB [emitted]
../icons/icon16.png 612 bytes [emitted]
../icons/icon_menu16.png 552 bytes [emitted]
../icons/icon_menu64.png 2.76 kB [emitted]
../icons/icon32.png 1.29 kB [emitted]
../icons/icon64.png 2.91 kB [emitted]
../index.html 315 bytes [emitted]
[133] ./content/commands-api.js 6.84 kB {0} [built]
[146] ./content/escape.js 5.11 kB {0} {6} [built]
[229] ./content/locatorBuilders.js 11.6 kB {3} [built]
[320] multi ./content/setup 28 bytes {5} [built]
[321] ./content/setup.js 1.28 kB {5} [built]
[322] multi ./content/commands-api 28 bytes {0} [built]
[385] multi ./background/background 28 bytes {4} [built]
[386] ./background/background.js 5.09 kB {4} [built]
[387] multi ./content/record 28 bytes {1} [built]
[388] ./content/record.js 19.5 kB {1} [built]
[389] ./content/record-api.js 9.7 kB {1} [built]
[390] ./content/prompt-recorder.js 2.41 kB {1} [built]
[391] multi ./content/escape 28 bytes {6} [built]
[392] multi react-hot-loader/patch ./neo/containers/Root 40 bytes {2} [built]
[396] ./neo/containers/Root/index.jsx 1.61 kB {2} [built]
+ 1075 hidden modules
Child html-webpack-plugin for "../index.html":
1 asset
[0] ../node_modules/html-webpack-plugin/lib/loader.js!./neo/index.html 720 bytes {0} [built]
+ 3 hidden modules
lerna success run Ran npm script 'build' in 4 packages:
lerna success - browser-webdriver
lerna success - selenium-ide-extension
lerna success - selenium-side-runner
lerna success - selianize
✨ Done in 130.43s.
$ npm start
> selenium-ide@ start /Users/jack/ui/selenium-ide
> cd packages/selenium-ide && yarn start
yarn run v1.13.0-20181121.1436
$ env NODE_ENV=test webpack-dev-server --hot
Project is running at http://localhost:8081/
webpack output is served from /assets/
Hash: a6db07ced022ebcba304
Version: webpack 3.12.0
Time: 43408ms
Asset Size Chunks Chunk Names
prompt.js 7.25 kB [emitted]
media/selenium_blue_white32@3x.84ab23d0.svg 3.62 kB [emitted]
media/selenium-ide.9b39b00c.svg 21.8 kB [emitted]
playback.js 617 kB 0 [emitted] [big] playback
record.js 298 kB 1 [emitted] [big] record
neo.js 18.7 MB 2 [emitted] [big] neo
atoms.js 5.16 MB 3 [emitted] [big] atoms
background.js 988 kB 4 [emitted] [big] background
polyfills.js 957 kB 5 [emitted] [big] polyfills
escape.js 898 kB 6 [emitted] [big] escape
highlight.css 952 bytes [emitted]
vendor/global.js 825 bytes [emitted]
vendor/selenium-browserdetect.js 5.27 kB [emitted]
media/selenium-ide.461193c2.ttf 7.44 kB [emitted]
../bootstrap.html 1.57 kB [emitted]
../indicator.html 1.03 kB [emitted]
indicator.js 694 bytes [emitted]
../manifest.json 1.74 kB [emitted]
../icons/icon_menu64.png 2.76 kB [emitted]
../icons/icon_menu32.png 1.22 kB [emitted]
../icons/icon128.png 5.88 kB [emitted]
../icons/icon_menu16.png 552 bytes [emitted]
../icons/icon16.png 612 bytes [emitted]
../icons/icon64.png 2.91 kB [emitted]
../icons/icon32.png 1.29 kB [emitted]
../index.html 315 bytes [emitted]
[40] (webpack)-dev-server/client?http://localhost:8081 7.93 kB {2} {3} {4} {5} {6} [built]
[41] (webpack)/hot/dev-server.js 1.61 kB {2} {3} {4} {5} {6} [built]
[170] ./src/content/commands-api.js 7.77 kB {0} [built]
[183] ./src/content/escape.js 5.96 kB {0} {6} [built]
[432] multi (webpack)-dev-server/client?http://localhost:8081 webpack/hot/dev-server ./content/setup 52 bytes {5} [built]
[433] ./src/content/setup.js 1.36 kB {5} [built]
[434] multi (webpack)-dev-server/client?http://localhost:8081 webpack/hot/dev-server ./content/commands-api 52 bytes {0} [built]
[497] multi (webpack)-dev-server/client?http://localhost:8081 webpack/hot/dev-server ./background/background 52 bytes {4} [built]
[498] ./src/background/background.js 6.57 kB {4} [built]
[499] multi (webpack)-dev-server/client?http://localhost:8081 webpack/hot/dev-server ./content/record 52 bytes {1} [built]
[500] ./src/content/record.js 23.2 kB {1} [built]
[503] multi (webpack)-dev-server/client?http://localhost:8081 webpack/hot/dev-server ./content/escape 52 bytes {6} [built]
[504] multi (webpack)-dev-server/client?http://localhost:8081 webpack/hot/dev-server react-hot-loader/patch ./neo/containers/Root 64 bytes {2} [built]
[505] ./node_modules/react-hot-loader/patch.js 40 bytes {2} [built]
[600] ./src/neo/containers/Root/index.jsx 1.82 kB {2} [built]
+ 1163 hidden modules
Child html-webpack-plugin for "../index.html":
1 asset
[0] ./node_modules/html-webpack-plugin/lib/loader.js!./src/neo/index.html 720 bytes {0} [built]
[1] ./node_modules/html-webpack-plugin/node_modules/lodash/lodash.js 540 kB {0} [built]
[2] (webpack)/buildin/global.js 509 bytes {0} [built]
[3] (webpack)/buildin/module.js 517 bytes {0} [built]
webpack: Compiled successfully.
