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							- import { identity } from '../util/identity';
 
- import { operate } from '../util/lift';
 
- import { createOperatorSubscriber } from './OperatorSubscriber';
 
- export function distinctUntilChanged(comparator, keySelector) {
 
-     if (keySelector === void 0) { keySelector = identity; }
 
-     comparator = comparator !== null && comparator !== void 0 ? comparator : defaultCompare;
 
-     return operate(function (source, subscriber) {
 
-         var previousKey;
 
-         var first = true;
 
-         source.subscribe(createOperatorSubscriber(subscriber, function (value) {
 
-             var currentKey = keySelector(value);
 
-             if (first || !comparator(previousKey, currentKey)) {
 
-                 first = false;
 
-                 previousKey = currentKey;
 
-                 subscriber.next(value);
 
-             }
 
-         }));
 
-     });
 
- }
 
- function defaultCompare(a, b) {
 
-     return a === b;
 
- }
 
- //# sourceMappingURL=distinctUntilChanged.js.map
 
 
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