Grunt Concat many files in many folders while maintaining folder structure - gruntjs

Question

I am using Grunt concat in my project. I want to combine files on a folder level.
E.G.
js >
parent >
child1 >
a.js
b.js
c.js
child2 >
a.js
b.js
into:
js >
parent >
child1 >
child1combined.js
child2 >
child2combined.js
is there a way of doing this without specifically adding each "child" in its own concat line?

Answer 1

I ended up doing the following I found in this post.
grunt.registerTask("taskName", "Task Description", function() {
// get all module directories
grunt.file.expand("src/js/parent/*").forEach(function (dir) {
// get the module name from the directory name
var dirName = dir.substr(dir.lastIndexOf('/')+1);
// get the current concat object from initConfig
var concat = grunt.config.get('concat') || {};
// create a subtask for each module, find all src files
// and combine into a single js file per module
concat[dirName] = {
src: [dir + '/**/*.js'],
dest: 'build/js/parent/' + dirName + '/combined.js'
};
// add module subtasks to the concat task in initConfig
grunt.config.set('concat', concat);
});
});
Then just call taskName from your registerTask.

Answer 2

Use globbing patterns in your concat task. To quote the linked documentation:
It is often impractical to specify all source filepaths individually,
so Grunt supports filename expansion (also know as globbing).

Answer 3

I know this topic is old, but I want to share my solution because I couldn't find a simple solution working as expected on the web.
concat: {
files: [
{
expand: true,
src: ["**/*.js"],
dest: "dest/js",
cwd: "src/js",
rename: function(dst, src) {
const srcParts = String(src).split("/");
let dstPath = "";
let dstName = srcParts[0].split(".")[0];
if (srcParts.length > 1) {
dstName = srcParts[srcParts.length - 2];
dstPath =
srcParts
.slice(0, srcParts.length - 1)
.join("/") + "/";
}
return `${dst}/${dstPath + dstName}.js`;
}
}
]
}
I hope this helps someone :)