function isBabelLoader(caller) { return caller && caller.name === "babel-loader" } module.exports = function (api) { if (api.env("test") && !api.caller(isBabelLoader)) { return { plugins: [ "@babel/plugin-proposal-class-properties", "@babel/plugin-proposal-nullish-coalescing-operator", "@babel/plugin-proposal-optional-chaining", ], presets: [ [ "@babel/preset-env", { targets: { node: "current", }, }, ], ], } } return {} }