Git命令出错

xcrun: error: invalid active developer path (/Library/Developer/CommandLineTools), missing xcrun at: /Library/Developer/CommandLineTools/usr/bin/xcrun

问题分析：上述错误为卸载Xcode导致
解决办法：可以通过如下命令修复xcode-select --install

Git命令出错

git push origin master
To git@github.com:qzmly100/repository-.git
! [rejected] master -> master (fetch first)
error: failed to push some refs to 'git@github.com:qzmly100/repository-.git'
hint: Updates were rejected because the remote contains work that you do
hint: not have locally. This is usually caused by another repository pushing
hint: to the same ref. You may want to first integrate the remote changes
hint: (e.g., 'git pull ...') before pushing again.
hint: See the 'Note about fast-forwards' in 'git push --help' for details.

问题分析：远程分支上存在本地分支中不存在的提交，往往是多人协作开发过程中遇到的问题
解决办法：先git pull后git push

Koa post请求错误

413 Request Entity Too Large

问题分析：koa-bodyparser中间件对各种POST请求的数据类型的大小做了限制
解决办法：app.use(bodyParser({formLimit: '1mb'}))

配置babel使得node可以使用import

(function (exports, require, module, __filename, __dirname) { import {
                                                              ^^^^^^

SyntaxError: Unexpected token import
    at createScript (vm.js:80:10)
    at Object.runInThisContext (vm.js:139:10)
    at Module._compile (module.js:607:28)
    at Object.Module._extensions..js (module.js:654:10)
    at Module.load (module.js:556:32)
    at tryModuleLoad (module.js:499:12)
    at Function.Module._load (module.js:491:3)
    at Function.Module.runMain (module.js:684:10)
    at startup (bootstrap_node.js:187:16)
    at bootstrap_node.js:608:3

问题分析：node使用CommonJS模式，胡无法使用import
解决办法：配置babel
第一步：

npm install --save-dev babel-cli babel-preset-es2015

第二步：配置packge.json

 "babel": "babel-node index.js"

第三步：配置.babelrc

{
  "presets": ["es2015"]
}

运行npm run babel，完美解决！

配置babel支持编译ES7新特性

第一步：

npm i -D babel-plugin-transform-runtime babel-runtime

第二步：配置编译命令

"build": "rimraf dist && babel src -s -D -d dist --presets env"

第三步：

{
  "plugins": ["transform-runtime",{"polifill": false, "regenerator": true}]
}  

配置babel支持展开运算符

#安装必要包
npm i babel-plugin-transform-object-rest-spread --save-dev

#配置.babelrc

{
  "plugins": ["transform-object-rest-spread"]
}

配置babel支持Decorator

第一步：

npm install babel-core babel-plugin-transform-decorators babel-plugin-transform-decorators-legacy -D

第二步：配置.babelrc

{
  "plugins": ["transform-decorators-legacy"]
}