grunt-contrib-copy throwing Warning: Arguments to path.join must be strings Use --force to continue

Question

I am trying to add a copy task to copy some js files. But I am getting following warning and files stopped copying.

Running "copy:group1" (copy) task
Warning: Arguments to path.join must be strings Use --force to continue.

Aborted due to warnings.

Gruntfile.js

module.exports = function(grunt) {

    grunt.initConfig({
        copy : {
                group1 : {
            files : [
                {
                        src : ['group1/js/*'],
                        dest : ['lib/group1/js/']
                    }
                ]
            }
        }
    });

    grunt.loadNpmTasks('grunt-contrib-copy');
};

Following is the result of grunt copy -v

Initializing
Command-line options: --verbose

Reading "Gruntfile.js" Gruntfile...OK

Registering Gruntfile tasks.
Initializing config...OK

Registering "grunt-contrib-copy" local Npm module tasks.
Reading /home/sasidhar/projects/grunt/node_modules/grunt-contrib-copy/package.json...OK
Parsing /home/sasidhar/projects/grunt/node_modules/grunt-contrib-copy/package.json...OK
Loading "copy.js" tasks...OK
+ copy
Loading "Gruntfile.js" tasks...OK
>> No tasks were registered or unregistered.

Running tasks: copy

Running "copy" task

Running "copy:group1" (copy) task
Verifying property copy.group1 exists in config...OK
Files: group1/js/js1.js, group1/js/js2.js, group1/js/js3.js -> lib/group1/js/
Options: processContent=false, processContentExclude=[]
Warning: Arguments to path.join must be strings Use --force to continue.

Aborted due to warnings.

I already referred to other Stackoverflow Question on the similar error. But my GruntJS is already having the fix mentioned by Sindre Sorhus.

Thanks in Advance.

Answer 1

Got it,

dest property must be a string. but not an Array.

Thanks.