PackedMessage

A memory-efficient compressed representation of a Message. Use PackedMessage when you need to retain many messages in memory (e.g., buffering, aggregation, or caching) and want to reduce memory overhead.

Create a PackedMessage by calling message.pack(). Unpack it back to a full Message when you need to access or modify the data.

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At a Glance

// Pack a message for efficient storage
const packed = message.pack();

// Store in a buffer or cache
messageBuffer.push(packed);

// Later: unpack and process
const restored = packed.unpack();
stream.emit(restored, OUTPUT_PORT);

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Properties

Property	Type	Description
type	DataDictionary	Reference to the data dictionary used when packing

const packed = message.pack();
stream.logInfo(`Packed type: ${packed.type}`);

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Methods

unpack()

Restores the packed message to a full Message instance.

Returns: Message

const packed = message.pack();
const restored = packed.unpack();

// restored is a full Message with all methods available
restored.getString(dataDictionary.type.Order.ID);
restored.addStatus(Severity.INFO, Status.create(VENDOR, 'RESTORED'));

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When to Use

Scenario	Approach
Buffering messages for batch processing	Pack to reduce memory
Caching messages in a queue service	Pack before storing
Aggregating many records before emitting	Pack intermediate results
Passing messages between processors	Use regular Message (no packing needed)

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Complete Example

let buffer = [];
const BATCH_SIZE = 100;

export function onMessage() {
    // Pack and buffer
    buffer.push(message.pack());

    // When buffer is full, process batch
    if (buffer.length >= BATCH_SIZE) {
        processBatch(buffer);
        buffer = [];
    }
}

export function onStreamEnd() {
    // Process remaining messages
    if (buffer.length > 0) {
        processBatch(buffer);
    }
}

function processBatch(packedMessages) {
    for (const packed of packedMessages) {
        const msg = packed.unpack();
        // Process...
        stream.emit(msg, OUTPUT_PORT);
    }
}

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See Also

• Message#pack — Create a PackedMessage from a Message
• Message#clone — Alternative: create a full copy instead of packing