Method constructor

packages/compiler-cli/src/ngtsc/program.ts:50–136

(
    rootNames: ReadonlyArray<string>,
    private options: NgCompilerOptions,
    delegateHost: api.CompilerHost,
    oldProgram?: NgtscProgram,
  )

  private incrementalStrategy: TrackedIncrementalBuildStrategy;

  constructor(
    rootNames: ReadonlyArray<string>,
    private options: NgCompilerOptions,
    delegateHost: api.CompilerHost,
    oldProgram?: NgtscProgram,
  ) {
    const perfRecorder = ActivePerfRecorder.zeroedToNow();

    perfRecorder.phase(PerfPhase.Setup);

    // First, check whether the current TS version is supported.
    if (!options.disableTypeScriptVersionCheck) {
      verifySupportedTypeScriptVersion();
    }

    // In local compilation mode there are almost always (many) emit errors due to imports that
    // cannot be resolved. So we should emit regardless.
    if (options.compilationMode === 'experimental-local') {
      options.noEmitOnError = false;
    }

    const reuseProgram = oldProgram?.compiler.getCurrentProgram();
    this.host = NgCompilerHost.wrap(delegateHost, rootNames, options, reuseProgram ?? null);

    if (reuseProgram !== undefined) {
      // Prior to reusing the old program, restore shim tagging for all its `ts.SourceFile`s.
      // TypeScript checks the `referencedFiles` of `ts.SourceFile`s for changes when evaluating
      // incremental reuse of data from the old program, so it's important that these match in order
      // to get the most benefit out of reuse.
      retagAllTsFiles(reuseProgram);
    }

    this.tsProgram = perfRecorder.inPhase(PerfPhase.TypeScriptProgramCreate, () =>
      ts.createProgram(this.host.inputFiles, options, this.host, reuseProgram),
    );

    perfRecorder.phase(PerfPhase.Unaccounted);
    perfRecorder.memory(PerfCheckpoint.TypeScriptProgramCreate);

    this.host.postProgramCreationCleanup();

    const programDriver = new TsCreateProgramDriver(
      this.tsProgram,
      this.host,
      this.options,
      this.host.shimExtensionPrefixes,
    );

    this.incrementalStrategy =
      oldProgram !== undefined
        ? oldProgram.incrementalStrategy.toNextBuildStrategy()
        : new TrackedIncrementalBuildStrategy();
    const modifiedResourceFiles = new Set<AbsoluteFsPath>();
    if (this.host.getModifiedResourceFiles !== undefined) {
      const strings = this.host.getModifiedResourceFiles();
      if (strings !== undefined) {
        for (const fileString of strings) {
          modifiedResourceFiles.add(absoluteFrom(fileString));