cli-logger.js 2.7 KB

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  1. "use strict";
  2. /**
  3. * @license
  4. * Copyright Google LLC All Rights Reserved.
  5. *
  6. * Use of this source code is governed by an MIT-style license that can be
  7. * found in the LICENSE file at https://angular.dev/license
  8. */
  9. Object.defineProperty(exports, "__esModule", { value: true });
  10. exports.createConsoleLogger = createConsoleLogger;
  11. const rxjs_1 = require("rxjs");
  12. const src_1 = require("../src");
  13. /**
  14. * A Logger that sends information to STDOUT and STDERR.
  15. */
  16. function createConsoleLogger(verbose = false, stdout = process.stdout, stderr = process.stderr, colors) {
  17. const logger = new src_1.logging.IndentLogger('cling');
  18. logger.pipe((0, rxjs_1.filter)((entry) => entry.level !== 'debug' || verbose)).subscribe((entry) => {
  19. const color = colors && colors[entry.level];
  20. let output = stdout;
  21. switch (entry.level) {
  22. case 'warn':
  23. case 'fatal':
  24. case 'error':
  25. output = stderr;
  26. break;
  27. }
  28. // If we do console.log(message) or process.stdout.write(message + '\n'), the process might
  29. // stop before the whole message is written and the stream is flushed. This happens when
  30. // streams are asynchronous.
  31. //
  32. // NodeJS IO streams are different depending on platform and usage. In POSIX environment,
  33. // for example, they're asynchronous when writing to a pipe, but synchronous when writing
  34. // to a TTY. In windows, it's the other way around. You can verify which is which with
  35. // stream.isTTY and platform, but this is not good enough.
  36. // In the async case, one should wait for the callback before sending more data or
  37. // continuing the process. In our case it would be rather hard to do (but not impossible).
  38. //
  39. // Instead we take the easy way out and simply chunk the message and call the write
  40. // function while the buffer drain itself asynchronously. With a smaller chunk size than
  41. // the buffer, we are mostly certain that it works. In this case, the chunk has been picked
  42. // as half a page size (4096/2 = 2048), minus some bytes for the color formatting.
  43. // On POSIX it seems the buffer is 2 pages (8192), but just to be sure (could be different
  44. // by platform).
  45. //
  46. // For more details, see https://nodejs.org/api/process.html#process_a_note_on_process_i_o
  47. const chunkSize = 2000; // Small chunk.
  48. let message = entry.message;
  49. while (message) {
  50. const chunk = message.slice(0, chunkSize);
  51. message = message.slice(chunkSize);
  52. output.write(color ? color(chunk) : chunk);
  53. }
  54. output.write('\n');
  55. });
  56. return logger;
  57. }