combineLatest.js 2.7 KB

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  1. import { Observable } from '../Observable';
  2. import { argsArgArrayOrObject } from '../util/argsArgArrayOrObject';
  3. import { from } from './from';
  4. import { identity } from '../util/identity';
  5. import { mapOneOrManyArgs } from '../util/mapOneOrManyArgs';
  6. import { popResultSelector, popScheduler } from '../util/args';
  7. import { createObject } from '../util/createObject';
  8. import { createOperatorSubscriber } from '../operators/OperatorSubscriber';
  9. import { executeSchedule } from '../util/executeSchedule';
  10. export function combineLatest() {
  11. var args = [];
  12. for (var _i = 0; _i < arguments.length; _i++) {
  13. args[_i] = arguments[_i];
  14. }
  15. var scheduler = popScheduler(args);
  16. var resultSelector = popResultSelector(args);
  17. var _a = argsArgArrayOrObject(args), observables = _a.args, keys = _a.keys;
  18. if (observables.length === 0) {
  19. return from([], scheduler);
  20. }
  21. var result = new Observable(combineLatestInit(observables, scheduler, keys
  22. ?
  23. function (values) { return createObject(keys, values); }
  24. :
  25. identity));
  26. return resultSelector ? result.pipe(mapOneOrManyArgs(resultSelector)) : result;
  27. }
  28. export function combineLatestInit(observables, scheduler, valueTransform) {
  29. if (valueTransform === void 0) { valueTransform = identity; }
  30. return function (subscriber) {
  31. maybeSchedule(scheduler, function () {
  32. var length = observables.length;
  33. var values = new Array(length);
  34. var active = length;
  35. var remainingFirstValues = length;
  36. var _loop_1 = function (i) {
  37. maybeSchedule(scheduler, function () {
  38. var source = from(observables[i], scheduler);
  39. var hasFirstValue = false;
  40. source.subscribe(createOperatorSubscriber(subscriber, function (value) {
  41. values[i] = value;
  42. if (!hasFirstValue) {
  43. hasFirstValue = true;
  44. remainingFirstValues--;
  45. }
  46. if (!remainingFirstValues) {
  47. subscriber.next(valueTransform(values.slice()));
  48. }
  49. }, function () {
  50. if (!--active) {
  51. subscriber.complete();
  52. }
  53. }));
  54. }, subscriber);
  55. };
  56. for (var i = 0; i < length; i++) {
  57. _loop_1(i);
  58. }
  59. }, subscriber);
  60. };
  61. }
  62. function maybeSchedule(scheduler, execute, subscription) {
  63. if (scheduler) {
  64. executeSchedule(subscription, scheduler, execute);
  65. }
  66. else {
  67. execute();
  68. }
  69. }
  70. //# sourceMappingURL=combineLatest.js.map