simple-keyboard/babel.config.js

module.exports = {
  presets: [
    ["@babel/env", {
      corejs:"3",
      useBuiltIns: 'usage',
      "targets": {
        "browsers": [
          "edge >= 16",
          "safari >= 9",
          "firefox >= 57",
          "ie >= 11",
          "ios >= 9",
          "chrome >= 49"
        ]
      },
    }]
  ],
  plugins: [
    ["@babel/plugin-proposal-class-properties"],
    ["@babel/plugin-transform-typescript"]
  ]
};