element-web/babel.config.js

module.exports = {
  "sourceMaps": true,
  "presets": [
    ["@babel/preset-env", {
      "targets": {
        "browsers": [
          "last 2 versions"
        ]
      }
    }],
    "@babel/preset-typescript",
    "@babel/preset-flow",
    "@babel/preset-react"
  ],
  "plugins": [
    ["@babel/plugin-proposal-decorators", {"legacy": true}],
    "@babel/plugin-proposal-export-default-from",
    "@babel/plugin-proposal-numeric-separator",
    "@babel/plugin-proposal-class-properties",
    "@babel/plugin-proposal-object-rest-spread",
    "@babel/plugin-transform-flow-comments",
    "@babel/plugin-syntax-dynamic-import",
    "@babel/plugin-transform-runtime"
  ]
};