54 lines
1.6 KiB
JavaScript
54 lines
1.6 KiB
JavaScript
import { Subscriber } from '../Subscriber';
|
|
export function distinctUntilChanged(compare, keySelector) {
|
|
return (source) => source.lift(new DistinctUntilChangedOperator(compare, keySelector));
|
|
}
|
|
class DistinctUntilChangedOperator {
|
|
constructor(compare, keySelector) {
|
|
this.compare = compare;
|
|
this.keySelector = keySelector;
|
|
}
|
|
call(subscriber, source) {
|
|
return source.subscribe(new DistinctUntilChangedSubscriber(subscriber, this.compare, this.keySelector));
|
|
}
|
|
}
|
|
class DistinctUntilChangedSubscriber extends Subscriber {
|
|
constructor(destination, compare, keySelector) {
|
|
super(destination);
|
|
this.keySelector = keySelector;
|
|
this.hasKey = false;
|
|
if (typeof compare === 'function') {
|
|
this.compare = compare;
|
|
}
|
|
}
|
|
compare(x, y) {
|
|
return x === y;
|
|
}
|
|
_next(value) {
|
|
let key;
|
|
try {
|
|
const { keySelector } = this;
|
|
key = keySelector ? keySelector(value) : value;
|
|
}
|
|
catch (err) {
|
|
return this.destination.error(err);
|
|
}
|
|
let result = false;
|
|
if (this.hasKey) {
|
|
try {
|
|
const { compare } = this;
|
|
result = compare(this.key, key);
|
|
}
|
|
catch (err) {
|
|
return this.destination.error(err);
|
|
}
|
|
}
|
|
else {
|
|
this.hasKey = true;
|
|
}
|
|
if (!result) {
|
|
this.key = key;
|
|
this.destination.next(value);
|
|
}
|
|
}
|
|
}
|
|
//# sourceMappingURL=distinctUntilChanged.js.map
|