Function generateEmptyCoverage

packages/jest-reporters/src/generateEmptyCoverage.ts:27–94

(
  source: string,
  filename: string,
  globalConfig: Config.GlobalConfig,
  config: Config.ProjectConfig,
  changedFiles?: Set<string>,
  sourcesRelatedToTestsInChangedFiles?: Set<string>,
)

    };

export default async function generateEmptyCoverage(
  source: string,
  filename: string,
  globalConfig: Config.GlobalConfig,
  config: Config.ProjectConfig,
  changedFiles?: Set<string>,
  sourcesRelatedToTestsInChangedFiles?: Set<string>,
): Promise<CoverageWorkerResult | null> {
  const coverageOptions = {
    changedFiles,
    collectCoverage: globalConfig.collectCoverage,
    collectCoverageFrom: globalConfig.collectCoverageFrom,
    coverageProvider: globalConfig.coverageProvider,
    globalRootDir: globalConfig.rootDir,
    sourcesRelatedToTestsInChangedFiles,
  };
  let coverageWorkerResult: CoverageWorkerResult | null = null;
  if (shouldInstrument(filename, coverageOptions, config)) {
    if (coverageOptions.coverageProvider === 'v8') {
      const stat = fs.statSync(filename);
      return {
        kind: 'V8Coverage',
        result: {
          functions: [
            {
              functionName: '(empty-report)',
              isBlockCoverage: true,
              ranges: [
                {
                  count: 0,
                  endOffset: stat.size,
                  startOffset: 0,
                },
              ],
            },
          ],
          scriptId: '0',
          url: filename,
        },
      };
    }

    const scriptTransformer = await createScriptTransformer(config);

    // Transform file with instrumentation to make sure initial coverage data is well mapped to original code.
    const {code} = await scriptTransformer.transformSourceAsync(
      filename,
      source,
      {
        instrument: true,
        supportsDynamicImport: true,
        supportsExportNamespaceFrom: true,
        supportsStaticESM: true,
        supportsTopLevelAwait: true,
      },
    );
    // TODO: consider passing AST
    const extracted = readInitialCoverage(code);