Visual Studio Code 能够自动检测grunt文件，无需配置就可以使用快捷键执行grunt编译任务：

VS Code can autodetect tasks from within Gulp, Grunt and Jake files. This adds their tasks to the task list without requiring additional configuration (unless you need to use a problem matcher, more on that in a moment).

但是如果grunt文件不在VS Code管理的根目录，那么用快捷键执行就会报错。 解决方法是在tasks.json中配置命令的cwd参数为grunt文件所在的文件夹。 其中${cwd}是VS Code预定的变量，代表当前的工作目录。

{
    // See https://go.microsoft.com/fwlink/?LinkId=733558
    // for the documentation about the tasks.json format
    "version": "0.1.0",
    "command": "grunt",
    "isShellCommand": true,
    "showOutput": "always",
    "options": {
        "cwd": "${cwd}/subfolder"
    }
}