Function stripExtension

packages/compiler-cli/src/ngtsc/file_system/src/util.ts:24–26

(path: T)

 * Remove a .ts, .d.ts, .tsx, or .js extension from a file name.
 */
export function stripExtension<T extends PathString>(path: T): T {
  return path.replace(TS_DTS_TSX_JS_EXTENSION, '') as T;
}

export function getSourceFileOrError(program: ts.Program, fileName: AbsoluteFsPath): ts.SourceFile {
  const sf = program.getSourceFile(fileName);