{ "presets": [ ["@babel/preset-env", { "useBuiltIns": "entry", "corejs": { "version": 3, "proposals": true } }], "@babel/preset-typescript" ], "plugins": [ "@babel/plugin-proposal-class-properties", "@babel/plugin-proposal-object-rest-spread", "@babel/plugin-transform-runtime", "@babel/plugin-proposal-nullish-coalescing-operator", "@babel/plugin-proposal-optional-chaining" ], "env": { "node": { "plugins": [ "add-module-exports" ] }, "test": { "plugins": [ "add-module-exports", "istanbul" ] } } }