Function getProjectStyleFile

src/cdk/schematics/utils/project-style-file.ts:23–53

(project: ProjectDefinition, extension?: string)

 * extension is specified, any style file with a valid extension will be returned.
 */
export function getProjectStyleFile(project: ProjectDefinition, extension?: string): string | null {
  const buildOptions = getProjectTargetOptions(project, 'build');
  const buildStyles = buildOptions['styles'];

  if (buildStyles && isJsonArray(buildStyles) && buildStyles.length) {
    const styles = buildStyles.map(s => (typeof s === 'string' ? s : (s as {input: string}).input));

    // Look for the default style file that is generated for new projects by the Angular CLI. This
    // default style file is usually called `styles.ext` unless it has been changed explicitly.
    const defaultMainStylePath = styles.find(file =>
      extension ? file === `styles.${extension}` : defaultStyleFileRegex.test(file),
    );

    if (defaultMainStylePath) {
      return normalize(defaultMainStylePath);
    }

    // If no default style file could be found, use the first style file that matches the given
    // extension. If no extension specified explicitly, we look for any file with a valid style
    // file extension.
    const fallbackStylePath = styles.find(file =>
      extension ? file.endsWith(`.${extension}`) : validStyleFileRegex.test(file),
    );

    if (fallbackStylePath) {
      return normalize(fallbackStylePath);
    }
  }

  return null;
}