BabylonJS/Babylon.js · error · Error

Could not find data in connection with unique id ${serialize

Error message

Could not find data in connection with unique id ${serializedConnection}

What it means

Thrown by ParseFlowGraph while reconnecting data outputs: a data output's connectedPointIds contains an id that has no matching data input in the dataInMap. Parsing stops because the graph topology cannot be reconstructed.

Source

Thrown at packages/dev/core/src/FlowGraph/flowGraphParser.ts:245

            return;
        }
        connection.connectTo(connectedConnection);
    };
    for (const block of blocks) {
        for (const dataIn of block.dataInputs) {
            for (const serializedConnection of dataIn.connectedPointIds) {
                const connection = dataOutMap.get(serializedConnection);
                if (!connection) {
                    throw new Error("Could not find data out connection with unique id " + serializedConnection);
                }
                connectIfNeeded(dataIn, connection);
            }
        }
        for (const dataOut of block.dataOutputs) {
            for (const serializedConnection of dataOut.connectedPointIds) {
                const connection = dataInMap.get(serializedConnection);
                if (!connection) {
                    throw new Error("Could not find data in connection with unique id " + serializedConnection);
                }
                connectIfNeeded(dataOut, connection);
            }
        }
        if (block instanceof FlowGraphExecutionBlock) {
            for (const signalOut of block.signalOutputs) {
                for (const serializedConnection of signalOut.connectedPointIds) {
                    const connection = signalInMap.get(serializedConnection);
                    if (!connection) {
                        throw new Error("Could not find signal in connection with unique id " + serializedConnection);
                    }
                    connectIfNeeded(signalOut, connection);
                }
            }
            for (const signalIn of block.signalInputs) {
                for (const serializedConnection of signalIn.connectedPointIds) {
                    const connection = signalOutMap.get(serializedConnection);
                    if (!connection) {

View on GitHub (pinned to 0592b347b8)

Solutions

Re-serialize the graph from the current library version
Include all blocks that own referenced data inputs in the serialization
Remove or correct dangling connectedPointIds entries in the JSON
Pre-validate that every data-output connection id maps to an existing data input uniqueId

Example fix

// before
{ "dataOutputs": [{ "name": "out", "connectedPointIds": ["deletedInput"] }] }
// after
{ "dataOutputs": [{ "name": "out", "connectedPointIds": [] }] }

Defensive patterns

Strategy: validation

Validate before calling

function validateOutConnections(serialized: any): string[] {
  const inIds = new Set(
    serialized.blocks.flatMap((b: any) => (b.dataInputs ?? []).map((i: any) => i.uniqueId))
  );
  return serialized.blocks
    .flatMap((b: any) => b.dataOutputs ?? [])
    .flatMap((o: any) => o.connectedPointIds ?? [])
    .filter((id: string) => !inIds.has(id));
}

Type guard

function allOutRefsResolve(serialized: any): boolean {
  const ins = new Set(serialized.blocks?.flatMap((b: any) => b.dataInputs?.map((i: any) => i.uniqueId) ?? []) ?? []);
  return serialized.blocks?.every((b: any) =>
    (b.dataOutputs ?? []).every((o: any) => (o.connectedPointIds ?? []).every((id: string) => ins.has(id)))
  ) ?? false;
}

Try / catch

try {
  const graph = ParseFlowGraph(serialized, coordinator);
} catch (e) {
  if (String(e.message).startsWith('Could not find data in connection')) {
    // dangling data-output reference; re-export the graph or drop the connection
  }
}

Prevention

Include every target block in serialized payloads so inputs are registered
Pre-validate data-output connection ids against existing data-input ids
Re-export graphs from the editor after renaming or removing block inputs

When it happens

Trigger: Parsing a serialized flow graph where some dataOut.connectedPointIds references a data-input uniqueId that is missing from dataInMap (target block absent, input renamed/removed, or edited serialization).

Common situations: Graph serialized in a newer library version where an input was removed or renamed; manual JSON edits; blocks deleted leaving dangling connections; payload truncated during storage/transport.

Related errors

AI-assisted analysis of BabylonJS/Babylon.js@0592b347b8 (2026-08-30). Data as JSON: /api/errors/e7b729d2e7ed7534. Report an issue: GitHub.