Loro timetravel

example.ts

// Get the snapshot for your doc
let snapshot = fetchSnapshot();

// Import your doc
const doc = new LoroDoc();
doc.import(snapshot);

// NOTE: Make sure that whenever you wrote to the doc you enabled timestamps.
//       This is important to make sure that we have a simple way to order
//       changes based on user intuition.
// 
// Like this, but it's not important for us here because we are just reading
// the doc
doc.setRecordTimestamp(true);

// Collect all changes from the document
const changes = doc.getAllChanges();

// Collect list of timestamps for all changes and sorted
const timestamps = [...changes.values()].flat().map(x => x.timestamp);
timestamps.sort((a, b) => a -b)

// Helper for getting the frontier for a timestamp
const getFrontierForTimestamp = (ts: number): { peer: string; counter: number }[] => {
    const frontiers = [] as { peer: string; counter: number }[];
    // Record the highest counter for each peer where it's change is not higher than
    // our target timestamp.
    changes.forEach((changes, peer) => {
        let counter = 0;
        for (const change of changes) {
            if (change.timestamp <= ts) {
                counter = Math.max(counter, change.counter + change.length - 1);
            }
        }
        if (counter > 0) {
            frontiers.push({ counter, peer });
        }
    });
    return frontiers;
};

// Now we get get the frontier for our slider index
let sliderIdx = 3;
const timestamp = timestamps[sliderIdx - 1];
const frontiers = getFrontierForTimestamp(timestamp);
doc.checkout(frontiers);