gruntfile is giving me errors in terminal - gruntjs

Question

learning grunt.js and I keep getting this error in Terminal.
Running "sass:dist" (sass) task
Warning: Path must be a string. Received undefined Use --force to continue.
Aborted due to warnings.
Here's the code. Any help would be great
module.exports = function(grunt) {
grunt.initConfig({
pkg: grunt.file.readJSON('package.json'),
/** Sass task **/
sass: {
dev: {
options: {
style: 'expanded',
sourcemap: 'none',
},
files: {
'compiled/style.css': 'sass/style.scss'
}
},
dist: {
options: {
style: 'compressed',
sourcemap: 'none',
},
files: {
'compiled/style-min.css': 'sass/style-min.scss'
}
}
},
/** Watch task **/
watch: {
css: {
files: '**/*.scss',
tasks: ['sass']
}
}
});
grunt.loadNpmTasks('grunt-contrib-sass');
grunt.loadNpmTasks('grunt-contrib-watch');
grunt.registerTask('default', ['watch']);
}
and here my json
{
"name": "millervolpe2016",
"version": "1.0.0",
"description": "Our company's new theme",
"main": "index.php",
"scripts": {
"test": "echo \"Error: no test specified\" && exit 1"
},
"repository": {
"type": "git",
"url": "git+https://github.com/jspraguemillervolpe/miller-volpe.git"
},
"keywords": [
"miller",
"volpe"
],
"author": "Jason Sprague",
"license": "ISC",
"bugs": {
"url": "https://github.com/jspraguemillervolpe/miller-volpe/issues"
},
"homepage": "https://github.com/jspraguemillervolpe/miller-volpe#readme",
"devDependencies": {
"grunt": "^1.0.1",
"grunt-autoprefixer": "^3.0.4",
"grunt-contrib-sass": "^1.0.0",
"grunt-contrib-watch": "^1.0.0"
},
"dependencies": {}
}

Answer 1

your sass dist: and files: should be like that:
files: {
'compiled/style-min.css': 'sass/style.scss'
}
The file you are pointing is sass/style.scss so you should use the same for dist and dev.
this file: 'sass/style-min.scss' does not exist in your project and in your dev sass you are using: 'sass/style.scss' , I did a test here and now sass:dist works fine if you change this.
let me know if that fix your problem.
thanks.