Method emit

packages/compiler-cli/src/ngtsc/program.ts:279–388

(
    opts?: api.EmitOptions<CbEmitRes> | undefined,
  )

  }

  emit<CbEmitRes extends ts.EmitResult>(
    opts?: api.EmitOptions<CbEmitRes> | undefined,
  ): ts.EmitResult {
    // Check if emission of the i18n messages bundle was requested.
    if (
      opts !== undefined &&
      opts.emitFlags !== undefined &&
      opts.emitFlags & api.EmitFlags.I18nBundle
    ) {
      this.emitXi18n();

      // `api.EmitFlags` is a View Engine compiler concept. We only pay attention to the absence of
      // the other flags here if i18n emit was requested (since this is usually done in the xi18n
      // flow, where we don't want to emit JS at all).
      if (!(opts.emitFlags & api.EmitFlags.JS)) {
        return {
          diagnostics: [],
          emitSkipped: true,
          emittedFiles: [],
        };
      }
    }

    const forceEmit = opts?.forceEmit ?? false;

    this.compiler.perfRecorder.memory(PerfCheckpoint.PreEmit);

    const res = this.compiler.perfRecorder.inPhase(PerfPhase.TypeScriptEmit, () => {
      const {transformers} = this.compiler.prepareEmit();
      const ignoreFiles = this.compiler.ignoreForEmit;
      const emitCallback = (opts?.emitCallback ??
        defaultEmitCallback) as api.TsEmitCallback<CbEmitRes>;

      const writeFile: ts.WriteFileCallback = (
        fileName: string,
        data: string,
        writeByteOrderMark: boolean,
        onError: ((message: string) => void) | undefined,
        sourceFiles: ReadonlyArray<ts.SourceFile> | undefined,
      ) => {
        if (sourceFiles !== undefined) {
          // Record successful writes for any `ts.SourceFile` (that's not a declaration file)
          // that's an input to this write.
          for (const writtenSf of sourceFiles) {
            if (writtenSf.isDeclarationFile) {
              continue;
            }

            this.compiler.incrementalCompilation.recordSuccessfulEmit(writtenSf);
          }
        }
        this.host.writeFile(fileName, data, writeByteOrderMark, onError, sourceFiles);
      };

      const customTransforms = opts && opts.customTransformers;
      const beforeTransforms = transformers.before || [];
      const afterDeclarationsTransforms = transformers.afterDeclarations;