.babelrc

{
  "env": {
    "test": {
      "presets": [
        ["@babel/preset-env", { "modules": "cjs" }],
        "@babel/preset-react",
        "@babel/preset-typescript"
      ],
      "plugins": [
        "@babel/plugin-transform-regenerator",
        "@babel/plugin-transform-runtime",
        "@babel/plugin-proposal-class-properties"
      ]
    },
    "build": {
      "plugins": [
        "babel-plugin-typescript-to-proptypes",
        // Due to the DTS build process, some aspects of the tsconfig don't match the
        // actual build result, specifically --downlevelIteration. This is due to their use of babel
        // over vanilla tsc. Due to this non-array iterators aren't properly transpiled when using
        // spread syntax. This plugin allows the use of spread syntax on non-array iterators.
        // E.G: [...new Set(myArray)]
        "@babel/plugin-transform-spread"
      ]
    },
  }
}