code: function getBaseDirectoriesFromRootDirs(rootDirs, basePath, scriptPath, ignoreCase) {
                  // Make all paths absolute/normalized if they are not already
                  rootDirs = ts.map(rootDirs, function (rootDirectory) { return ts.normalizePath(ts.isRootedDiskPath(rootDirectory) ? rootDirectory : ts.combinePaths(basePath, rootDirectory)); });
                  // Determine the path to the directory containing the script relative to the root directory it is contained within
                  var relativeDirectory;
                  for (var _i = 0, rootDirs_1 = rootDirs; _i < rootDirs_1.length; _i++) {
                      var rootDirectory = rootDirs_1[_i];
                      if (ts.containsPath(rootDirectory, scriptPath, basePath, ignoreCase)) {
                          relativeDirectory = scriptPath.substr(rootDirectory.length);
                          break;
                      }
                  }
                  // Now find a path for each potential directory that is to be merged with the one containing the script
                  return ts.deduplicate(ts.map(rootDirs, function (rootDirectory) { return ts.combinePaths(rootDirectory, relativeDirectory); }));
              }
docs: Takes a script path and returns paths for all potential folders that could be merged with its
  containing folder via the "rootDirs" compiler option