.babelrc

{  
    "presets": [
        [
            "env", {
                "targets": {
                    "ie": 9,
                    "chrome": 27,
                    "firefox": 30,
                    "safari": 5,
                    "opera": 23
                },
                "modules": false,
                "loose":   true
            }
        ]
    ],

    "plugins": [
        [ "transform-flow-strip-types", { "loose": true } ],
        [ "transform-object-rest-spread", { "loose": true } ],
        [ "syntax-object-rest-spread", { "loose": true } ],
        [ "transform-class-properties", { "loose": true } ],
        [ "transform-es3-property-literals", { "loose": true } ],
        [ "transform-es3-member-expression-literals", { "loose": true } ],
        [ "transform-es2015-for-of", { "loose": true } ],
        [ "transform-decorators-legacy", { "loose": true } ],
        [ "babel-plugin-transform-react-jsx", { "pragma": "jsxDom" } ]
    ],

    "env": {
        "test": {
            "plugins": [
                [ "istanbul", { "only": "./src" } ]
            ]
        }
    }
}