Liveblocks: A script that pushes 150 list items simultaneously using 150 simultaneous mutateStorage calls. The expected result is 150 items being pushed to the array, since we don't override the LiveList, we only mutate it by pushing items. The real result is not all items being pushed.

pushLiveListItems.ts

import { Liveblocks, LiveList } from "@liveblocks/node";

/**
 * This script is used to push a list of items to a Liveblocks room.
 * We're mutating the list, by pushing 150 items, so the final list should have 150 items,
 * but we never get 150 items back, it's always less.
 *
 * For running the script use Node 24 (it allows to run .ts directly using node only):
 *
 * ```node
 * LB_SECRET=<your-secret> node pushLiveListItems.ts
 * ```
 */

const numberOfItemsToInsert = 150;
const roomId = "live-list-insertion-test" + crypto.randomUUID();

const secret = process.env.LB_SECRET;
if (!secret) {
  console.error("LB_SECRET environment variable is not set.");
  process.exit(1);
}

const liveblocks = new Liveblocks({ secret });

async function pushOne(index: number): Promise<void> {
  await liveblocks.mutateStorage(roomId, async ({ root }) => {
    const list = root.get("list") as LiveList<string>;
    list.push(index.toString());
  });
}

async function main() {
  // Initialize the room
  await liveblocks.getOrCreateRoom(roomId, {
    defaultAccesses: [],
  });
  await liveblocks.mutateStorage(roomId, async ({ root }) => {
    root.set("list", new LiveList<string>([]));
  });

  // Push the items
  console.log(
    `Pushing ${numberOfItemsToInsert} item(s) concurrently to room "${roomId}" at path "list"…`
  );

  const ops = Array.from({ length: numberOfItemsToInsert }, (_, i) =>
    pushOne(i)
  );
  const results = await Promise.allSettled(ops);

  // Fetch the storage again and check if all items have been inserted
  const { list } = await liveblocks.getStorageDocument(roomId, "json");
  const numberOfItemsInserted = (list as string[])?.length ?? 0;
  console.log(
    `Items count in the list after inserting ${numberOfItemsToInsert} items: ${numberOfItemsInserted}`
  );

  const succeeded = results.filter((r) => r.status === "fulfilled").length;
  const failed = results.length - succeeded;

  console.log(
    `Succeeded: ${succeeded}, Failed: ${failed}, Missing: ${
      numberOfItemsToInsert - numberOfItemsInserted
    }`
  );

  if (failed > 0) {
    // Surface at least one failure
    for (const r of results) {
      if (r.status === "rejected") {
        console.error("Example error:", r.reason);
        break;
      }
    }
    process.exitCode = 1;
  }
}

await main();