Not parsing ES6

[franciscop]

It is not parsing ES6 properly in my config:

My relevant code. Inside initConfig:

jshint: {
  target: 'assets/*.jsx',
  options: {
    ignores: [],
    additionalSuffixes: ['.js']
  }
},

Then at the end, after initConfig({ ... }):

grunt.loadNpmTasks('grunt-contrib-watch');
grunt.loadNpmTasks('grunt-contrib-sass');
grunt.loadNpmTasks('grunt-jsxhint');
grunt.loadNpmTasks('grunt-shell');
grunt.loadNpmTasks('grunt-notify');
grunt.registerTask('default', ['jshint', 'shell', 'sass', 'notify:build']);

I've tried tweaking and changing few things but still the same error