Jest

## Jest Setup for a Monorepo

Out of the box, Jest mostly works in a Monorepo environment, with the exception of a few Babel plugins so that (as an example) TypeScript works. Needs: @babel/preset-env (Babel will transform whatever it needs to transform based on the build target, e.g. TypeScript, IE11, ES6, Node10, etc.) @babel/preset-typescript (Babel will strip out the symbols that are specific to TypeScript) The root-level .babelrc file would look like: { "presets": [ ["@babel/preset-env", { "targets": { "node": 10 } }], "@babel/preset-typescript" ] } The target above is arbitrary, and can be anything (or nothing). ...