WebSocket.binaryType
  The WebSocket.binaryType property controls the type of
  binary data being received over the WebSocket connection.
Value
A DOMString:
"blob"- 
    
Use
Blobobjects for binary data. This is the default value. "arraybuffer"- 
    
Use
ArrayBufferobjects for binary data. 
Examples
// Create WebSocket connection.
const socket = new WebSocket("ws://localhost:8080");
// Change binary type from "blob" to "arraybuffer"
socket.binaryType = "arraybuffer";
// Listen for messages
socket.addEventListener("message", function (event) {
    if(event.data instanceof ArrayBuffer) {
        // binary frame
        const view = new DataView(event.data);
        console.log(view.getInt32(0));
    } else {
        // text frame
        console.log(event.data);
    }
});
Specifications
| Specification | 
|---|
| HTML Standard  # dom-websocket-binarytype-dev  | 
Browser compatibility
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