执行以下几行，以解决ng未找到和未定义版本的问题

卸载-g angular-cli

卸载angular-cli

NPM缓存清理

安装-g @angular/cli@latest

关闭CMD并再次以管理员权限打开或重新启动系统。

今天我也遇到了同样的问题，我走过了下面这条路—— (%USERPROFILE%\AppData\Roaming\npm)，当我清除npm目录下的所有内容时，才知道有一些垃圾数据。现在当我运行(npm安装命令再次)。现在一切正常。

我根据图解决了这个问题:

在CMD下运行

 npm install -g @angular/cli

然后

(在Windows 10中打开)控制面板\所有控制面板项\系统 或按图

步骤1:

第二步:

步骤3:

目的:

添加缺少的ng路径

下面是你需要添加的新环境变量:c:\ users \ pk\ appdata \漫游\npm\node_modules\@angular\cli\bin

最后，重新启动所有打开的命令提示符并重试。

I was having the same issue when tried with the syntax "ng new " and solved that simply by updating the existing node version from 5.x.x to 8.x.x. After successful updation of node, the syntax worked perfectly for me. Please update the existing version of node. As it is clearly mentioned in angular documentation that these commands require the node version >= 6.9.x. For reference please check https://angular.io/guide/quickstart. It clearly states "Verify that you are running at least node 6.9.x and npm 3.x.x by running node -v and npm -v in a terminal/console window. Older versions produce errors, but newer versions are fine".

设置路径= % %路径;C: \ \ \ AppData \ \ npm漫游用户