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DataDictionary

The DataDictionary provides access to all data structures defined in your layline.io project — message types, record formats, and field definitions. It is available globally as dataDictionary in every JavaScript processor.

Use it to create new messages, navigate type hierarchies, and access field metadata.

At a Glance​

// Navigate to a specific type
const detailType = dataDictionary.type.MyFormat.Detail;

// Create a new message from that type
const newMessage = dataDictionary.createMessage(detailType);

// Populate and emit
newMessage.data.RECORD_TYPE = "D";
stream.emit(newMessage, OUTPUT_PORT);

Properties​

PropertyTypeDescription
typeDataDictionaryTypesAccess all data dictionary types defined in your project

type​

Navigate your data dictionary hierarchy through this property. The structure mirrors your project's format and data dictionary definitions.

// Access a specific record type
const headerType = dataDictionary.type.MyFormat.Header;
const detailType = dataDictionary.type.MyFormat.Detail;

// Access nested fields (returns DataDictionaryEntity for use with Message methods)
const recordTypeField = dataDictionary.type.MyFormat.Detail.RECORD_TYPE;
const nameField       = dataDictionary.type.MyFormat.Detail.NAME;

// Use with Message getters/setters
const name = message.getString(nameField);

Methods​

createMessage(entity)​

Creates a new Message from a data dictionary structure. Use this when you need to construct messages for splitting, aggregation, or transformation.

ParameterTypeDescription
entityDataDictionaryEntityThe data dictionary path to the structure you want to instantiate

Returns: Message

// Create a message from a specific type
const header = dataDictionary.createMessage(dataDictionary.type.MyFormat.Header);

// Populate fields
header.data.RECORD_TYPE = "HDR";
header.data.TIMESTAMP   = new Date();

// Emit
stream.emit(header, OUTPUT_PORT);

See Also​

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