simplify module mapper (#610)

internal/config/src/jest/get-module-map.js

@@ -1,31 +1,24 @@
 const getPackages = require('get-monorepo-packages')
-
+const path = require('path')
 // do not map modules in CI to catch any package install bugs (slower)... not in use ATM
 const doNotMapPackages = process.env.JEST_SKIP_PACKAGE_MAP === 'true'
 
 /**
  * Create module mapping that resolve packages for ts-jest so typescript compilation happens in-memory
- *
  */
 const getJestModuleMap = ({ skipPackageMap = doNotMapPackages } = {}) => {
-  // get listing of packages in the mono repo
-
   /**
    * @param location - e.g. "packages/core"
    */
-
   const createPackageMappedPath = (location) => {
-    // if packageRoot is the global jest file (using projects), our mappers suddenly need
-    // to be relative to each project -- I have no idea why, seems unintuitive.
-    // If not root config, equiv to running "yarn test" in an individual package repo (rootDir will be the root package.json)
-    const moduleBasePath = global.JEST_ROOT_CONFIG
-      ? '<rootDir>/../..'
-      : '<rootDir>'
-    return `${moduleBasePath}/${location}/src/$1`
+    const base = path.basename(location) // get base folder name of a package e.g. "core" or "browser"
+    return `<rootDir>/../${base}/src/$1`
   }
+
   // for the sake of getPackages working correctly during a project-wide test run, the working directory must be hardcoded to the root
   const packageRoot = global.JEST_ROOT_CONFIG ? '.' : '../../'
-  const moduleNameMapper = getPackages(packageRoot).reduce(
+  const packages = getPackages(packageRoot)
+  const moduleNameMapper = packages.reduce(
     (acc, el) => ({
       ...acc,
       [`${el.package.name}(.*)$`]: createPackageMappedPath(el.location),