rxjs
Version:
Reactive Extensions for modern JavaScript
18 lines • 712 B
JavaScript
import { operate } from '../util/lift';
import { OperatorSubscriber } from './OperatorSubscriber';
export function distinctUntilChanged(compare, keySelector) {
compare = compare !== null && compare !== void 0 ? compare : defaultCompare;
return operate((source, subscriber) => {
let prev;
let first = true;
source.subscribe(new OperatorSubscriber(subscriber, (value) => {
((first && ((prev = value), 1)) || !compare(prev, (prev = keySelector ? keySelector(value) : value))) &&
subscriber.next(value);
first = false;
}));
});
}
function defaultCompare(a, b) {
return a === b;
}
//# sourceMappingURL=distinctUntilChanged.js.map