static keyword throwing error in grunt-babel

Question

I tried to trans-pile below code in try it out tab of babeljs -

    class aboutController{
      constructor(ajaxService){
        this.ajaxService = ajaxService;
        this.printLog();
      }

      printLog(){
        this.ajaxService.log();
      }

      static $inject = ["ajaxService"];
    }

The static keyword got trans-piled to

{
  key: "$inject",
  value: ["ajaxService"],
  enumerable: true
}

I then tried out grunt-babel task to automate the build. My gruntfile.js looks like this -

module.exports = function(grunt){
grunt.initConfig({
    pkg: grunt.file.readJSON('package.json'),
    babel: {
        options: {
            sourceMap: true,
            highlightCode: true
        },
        es6: {
            files: [
                {
                    expand: true,
                    src: ['components/**/*.es6'],
                    ext: '.js'
                }
            ]
        }
    },
    watch: {
        scripts: {
            files: ['components/**/*.es6'],
            tasks:['babel']
        }
    }
});

require("load-grunt-tasks")(grunt);
grunt.registerTask("default", ["babel", "watch"]);
}

But now the static keyword is giving error, when I remove the static keyword, the build is passing. Any idea how to fix this. Is grunt-babel outdated?

Here is how my packahe.json looks like -

{
"name": "babeles6",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
},
"author": "",
"license": "ISC",
"devDependencies": {
    "grunt": "~0.4.2",
    "grunt-babel": "^5.0.1",
    "grunt-contrib-watch": "^0.6.1",
    "load-grunt-tasks": "^3.2.0"
}
}

Answer 1

ES6 class syntax only supports methods. Your example uses ES7-proposed class properties. They are enabled in Babel on "Try it out" if you have "Experimental" checked.

 static $inject = ["ajaxService"];

will only work if you specifically enable es7.classProperties or broadly enabled all stage 0 transforms.

The ES6-compatible approach would be

static get $inject(){
    return ["ajaxService"];
}