Function register

packages/node/src/typescript.ts:127–463

(opts: Options = {})

 * Register TypeScript compiler.
 */
export function register(opts: Options = {}): Register {
  const options = Object.assign({}, DEFAULTS, opts);

  const ignoreDiagnostics = [
    6059, // "'rootDir' is expected to contain all source files."
    18002, // "The 'files' list in config file is empty."
    18003, // "No inputs were found in config file."
    ...(options.ignoreDiagnostics || []),
  ].map(Number);

  // Require the TypeScript compiler and configuration.
  const cwd = options.basePath || process.cwd();
  let compiler: string;
  try {
    compiler = require_.resolve(options.compiler || 'typescript', {
      paths: [options.project || cwd],
    });
  } catch (_e) {
    compiler = 'typescript';
  }
  const ts: typeof _ts = require_(compiler);
  if (compiler === 'typescript') {
    console.log(
      `Using built-in TypeScript ${ts.version} since "typescript" is missing from "devDependencies"`
    );
  } else {
    console.log(`Using TypeScript ${ts.version} (local user-provided)`);
  }
  const transformers = options.transformers || undefined;
  const readFile = options.readFile || ts.sys.readFile;
  const fileExists = options.fileExists || ts.sys.fileExists;

  const formatDiagnostics =
    process.stdout.isTTY || options.pretty
      ? ts.formatDiagnosticsWithColorAndContext
      : ts.formatDiagnostics;

  const diagnosticHost: _ts.FormatDiagnosticsHost = {
    getNewLine: () => ts.sys.newLine,
    getCurrentDirectory: () => cwd,
    getCanonicalFileName: path => path,
  };

  function reportTSError(
    diagnostics: _ts.Diagnostic[],
    shouldExit: boolean | undefined
  ) {
    if (!diagnostics || diagnostics.length === 0) {
      return;
    }
    const message = formatDiagnostics(diagnostics, diagnosticHost);

    if (shouldExit) {
      throw new NowBuildError({ code: 'NODE_TYPESCRIPT_ERROR', message });
    } else {
      // Print error in red color and continue execution.
      console.error(message);
    }