Upgrade to babel 7

babel/babel 🐠 Babel is a compiler for writing next generation JavaScript. - babel/babelgithub.com

{
    "presets": [
        "@babel/preset-env",
        "@babel/preset-react"
    ],
    "plugins": [
        "@babel/plugin-transform-runtime",
        [
            "@babel/plugin-proposal-decorators",
            {
                "legacy": *true
            *}
        ],
        "@babel/plugin-proposal-function-sent",
        "@babel/plugin-proposal-export-namespace-from",
        "@babel/plugin-proposal-numeric-separator",
        "@babel/plugin-proposal-throw-expressions",
        "@babel/plugin-syntax-dynamic-import",
        "@babel/plugin-syntax-import-meta",
        [
            "@babel/plugin-proposal-class-properties",
            {
                "loose": *false
            *}
        ],
        "@babel/plugin-proposal-json-strings",
        "@babel/plugin-transform-modules-commonjs"
    ],
    "env": {
        "development": {
            "plugins": [
                "react-hot-loader/babel"
            ]
        }
    }
}

https://github.com/zloirock/core-js/blob/master/docs/2019-03-19-core-js-3-babel-and-a-look-into-the-future.md