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distinct

distinct

rxjs.dev

Passes only values with a key not seen for the whole subscription.

Signature

distinct(keySelector?: (value: T) => K): MonoTypeOperatorFunction

What it does

Keeps a Set of keys already seen. If a key has appeared before, the value is dropped; if it's new, it passes on.

When to use

Removing duplicate ids from an event list, keeping the first unique values, guarding against repeat clicks on the same entity.

Gotcha

The Set grows until the stream completes. For infinite streams use the flushes parameter, or distinctUntilChanged if you only need to compare neighboring values.

See also

distinctUntilChanged, distinctUntilKeyChanged

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