message: refactor(ivy): move ngcc `rootDirs` computation into a function
  PR Close
diff: @@ -62,14 +62,7 @@ export class Transformer {
  // Create the TS program and necessary helpers.
  // TODO : create a custom compiler host that reads from .bak files if available.
  const host = ts.createCompilerHost(options);
  - let rootDirs: string[]|undefined = undefined;
  - if (options.rootDirs !== undefined) {
  - rootDirs = options.rootDirs;
  - } else if (options.rootDir !== undefined) {
  - rootDirs = [options.rootDir];
  - } else {
  - rootDirs = [host.getCurrentDirectory()];
  - }
  + const rootDirs = this.getRootDirs(host, options);
  const entryPointFilePath = entryPoint[format];
  if (!entryPointFilePath) {
  throw new Error(
  @@ -113,6 +106,16 @@ export class Transformer {
  writeMarkerFile(entryPoint, format);
  }
  + getRootDirs(host: ts.CompilerHost, options: ts.CompilerOptions) {
  + if (options.rootDirs !== undefined) {
  + return options.rootDirs;
  + } else if (options.rootDir !== undefined) {
  + return [options.rootDir];
  + } else {
  + return [host.getCurrentDirectory()];
  + }
  + }
  +
  getHost(isCore: boolean, format: string, program: ts.Program, dtsMapper: DtsMapper):
  NgccReflectionHost {
  switch (format) {
  