StoreBeforeCreateHandler • tldraw Docs

Handler function called before a record is created in the store. The handler receives the record to be created and can return a modified version. Use this to validate, transform, or modify records before they are added to the store.

type StoreBeforeCreateHandler<R extends UnknownRecord> = (
  record: R,
  source: "remote" | "user",
) => R;

Example

const handler: StoreBeforeCreateHandler<MyRecord> = (record, source) => {
  // Ensure all user-created records have a timestamp
  if (source === "user" && !record.createdAt) {
    return { ...record, createdAt: Date.now() };
  }
  return record;
};

Parameters

Name	Description
`record`	The record about to be created
`source`	Whether the change originated from 'user' interaction or 'remote' synchronization