How to resolve "Path must be a string. Received null Use" error message when execute grunt script?

• Run the grunt script, error message as shown below is displayed

Running "jshint:all" (jshint) task
Warning: Path must be a string. Received null Use --force to continue.
Aborted due to warnings.

• To resolve this, add the script as shown below to jshint section

options:{
 reporterOutput:''
},

• Please refer to the sample source, it will work perfectly

grunt.initConfig({
 jshint:{
  options:{
    reporterOutput:''
   },
   all:['script.js']
  }
 });