卡住老半天了，解决不了。。。
lichdeMacBook-Pro:syFront lichking2015$ cnpm i webpack-dev-server --save-dev ✖ Install fail! Error: [webpack-dev-server@3.1.4 › webpack@4.8.2 › @webassemblyjs/wasm-edit@1.4.2 › @webassemblyjs/helper-buf fer@1.4.2] Can't find package @webassemblyjs/helper-buffer's version: 1.4.2 Error: [webpack-dev-server@3.1.4 › webpack@4.8.2 › @webassemblyjs/wasm-edit@1.4.2 › @webassemblyjs/helper-buffer@1.4.2] Can't find package @webassemblyjs/helper-buffer's version: 1.4.2 at resolve (/usr/local/lib/node_modules/cnpm/node_modules/npminstall/lib/download/npm.js:91:11) at resolve.next (<anonymous>) at onFulfilled (/usr/local/lib/node_modules/cnpm/node_modules/co/index.js:65:19) at <anonymous> at process._tickCallback (internal/process/next_tick.js:118:7) npminstall version: 3.5.0 npminstall args: /usr/local/bin/node /usr/local/lib/node_modules/cnpm/node_modules/npminstall/bin/install.js --fix-bug-versio ns --china --userconfig=/Users/lichking2015/.cnpmrc --disturl=https://npm.taobao.org/mirrors/node --registry=https://registry .npm.taobao.org webpack-dev-server --save-dev
问题解决了，过程：
1、卸载了cnpm，并重新安装
2、之前在我的本地环境下，安装了webpack，版本是4.5.0。把本地这个去掉了，使用全局的webpack。就好使了
具体原因还不太清楚，是不是本地的webpack与全局webpack会有冲突？
好使了：
lichdeMacBook-Pro:test1 lichking2015$ cnpm i webpack-dev-server --save-dev
✔ Installed 1 packages
✔ Linked 0 latest versions
✔ Run 0 scripts
✔ All packages installed (used 523ms, speed 273.9kB/s, json 1(143.25kB), tarball 0B)