Set the flatten property to false.
There is a clear explanation on the grunt copy github readme
https://github.com/gruntjs/grunt-contrib-copy
Excerpt:
$ grunt copy
Running "copy:main" (copy) task
Created 1 directories, copied 1 files
Done, without errors.
$ tree -I node_modules
.
├── Gruntfile.js
├── dest
│ └── src
│ ├── a
│ └── subdir
└── src
├── a
└── subdir
└── b
5 directories, 4 files
Flattening the filepath output:
copy: {
main: {
expand: true,
cwd: 'src/',
src: '**',
dest: 'dest/',
flatten: true,
filter: 'isFile',
},
},
$ grunt copy
Running "copy:main" (copy) task
Copied 2 files
Done, without errors.
$ tree -I node_modules
.
├── Gruntfile.js
├── dest
│ ├── a
│ └── b
└── src
├── a
└── subdir
└── b
3 directories, 5 files