Rx.Observable.prototype.distinctUntilChanged([keySelector], [comparer])
Returns an observable sequence that contains only distinct contiguous elements according to the keySelector and the comparer.
Arguments
[keySelector]
(Function
): A function to compute the comparison key for each element. If not provided, it projects the value.[comparer]
(Function
): Equality comparer for computed key values. If not provided, defaults to an equality comparer function.
Returns
(Observable
): An observable sequence only containing the distinct contiguous elements, based on a computed key value, from the source sequence.
Example
/* Without key selector */
var source = Rx.Observable.of(42, 42, 24, 24)
.distinctUntilChanged();
var subscription = source.subscribe(
function (x) {
console.log('Next: %s', x);
},
function (err) {
console.log('Error: %s', err);
},
function () {
console.log('Completed');
});
// => Next: 42
// => Next: 24
// => Completed
/* With key selector */
var source = Rx.Observable.of({value: 42}, {value: 42}, {value: 24}, {value: 24})
.distinctUntilChanged(function (x) { return x.value; });
var subscription = source.subscribe(
function (x) {
console.log('Next: ' + x.toString());
},
function (err) {
console.log('Error: ' + err);
},
function () {
console.log('Completed');
});
// => Next: { value: 42 }
// => Next: { value: 24 }
// => Completed
/* With comparer */
var source = Rx.Observable.of({value: 42}, {value: 42}, {value: 24}, {value: 24})
.distinctUntilChanged(function (x) { return x.value; }, function (a,b) { return a !== b; });
var subscription = source.subscribe(
function (x) {
console.dir('Next: ' + x.toString());
},
function (err) {
console.log('Error: ' + err);
},
function () {
console.log('Completed');
});
// => Next: { value: 42 }
// => Next: { value: 42 }
// => Completed
Location
File:
Dist:
NPM Packages:
NuGet Packages:
Unit Tests: