Method callback

packages/webpack-cli/src/webpack-cli.ts:3479–3533

(error, stats)

    }

    const callback: WebpackCallback = (error, stats): void => {
      if (error) {
        this.logger.error(error);
        process.exit(2);
      }

      if (stats && (stats.hasErrors() || (options.failOnWarnings && stats.hasWarnings()))) {
        process.exitCode = 1;
      }

      if (!compiler || !stats) {
        return;
      }

      const statsOptions = this.isMultipleCompiler(compiler)
        ? {
            children: compiler.compilers.map((compiler) => compiler.options.stats),
          }
        : compiler.options.stats;

      if (options.json) {
        const handleWriteError = (error: Error) => {
          this.logger.error(error);
          process.exit(2);
        };

        if (options.json === true) {
          Readable.from(stringifyChunked(stats.toJson(statsOptions as StatsOptions)))
            .on("error", handleWriteError)
            .pipe(process.stdout)
            .on("error", handleWriteError)
            .on("close", () => process.stdout.write("\n"));
        } else {
          Readable.from(stringifyChunked(stats.toJson(statsOptions as StatsOptions)))
            .on("error", handleWriteError)
            .pipe(fs.createWriteStream(options.json))
            .on("error", handleWriteError)
            // Use stderr to logging
            .on("close", () => {
              process.stderr.write(
                `[webpack-cli] ${this.colors.green(
                  `stats are successfully stored as json to ${options.json}`,
                )}\n`,
              );
            });
        }
      } else {
        const printedStats = stats.toString(statsOptions);

        // Avoid extra empty line when `stats: 'none'`
        if (printedStats) {
          this.logger.raw(printedStats);
        }
      }
    };

    const env =
      isWatchCommand || options.watch