All files / app/features/messages useMarkLastSeen.ts

100% Statements 16/16
100% Branches 2/2
100% Functions 5/5
100% Lines 16/16

Press n or j to go to the next uncovered block, b, p or k for the previous block.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 441x   1x     1x       1x       174x       174x 26x 13x             174x   13x 2x         174x 45x 2x 2x       174x    
import { debounce } from "@material-ui/core";
import { Empty } from "google-protobuf/google/protobuf/empty_pb";
import { useEffect, useMemo, useRef } from "react";
import { UseMutateFunction } from "react-query";
 
import { MARK_LAST_SEEN_TIMEOUT } from "./constants";
 
export type MarkLastSeenVariables = number;
 
export default function useMarkLastSeen(
  markLastSeenMutate: UseMutateFunction<Empty, Error, MarkLastSeenVariables>,
  lastSeenMessageId?: number
) {
  const maxMessageIdRef = useRef(0);
  // Sync with latest lastSeenMessageId so anything below that ID doesn't get tried again.
  // Needed since lastSeenMessageId comes from react query which is initially
  // undefined so can't do useRef(lastSeenMessageId).
  useEffect(() => {
    if (lastSeenMessageId) {
      maxMessageIdRef.current = Math.max(
        maxMessageIdRef.current,
        lastSeenMessageId
      );
    }
  }, [lastSeenMessageId]);
 
  const debouncedMarkLastSeen = useMemo(
    () =>
      debounce((messageId: number) => {
        markLastSeenMutate(messageId);
      }, MARK_LAST_SEEN_TIMEOUT),
    [markLastSeenMutate]
  );
 
  const markLastSeen = (messageId: number) => {
    if (messageId > maxMessageIdRef.current) {
      maxMessageIdRef.current = messageId;
      debouncedMarkLastSeen(messageId);
    }
  };
 
  return { markLastSeen };
}