how to send long complex array with socket.io?

I have complex an array containing lots of base64 data. and I send this array to server with socket.io. If I send an array containing one or two base64 data. the function is working successfully. but if I send an array containing lots of base64 data. function does not react.

my purpose

  • client will prepare templates.
  • When the client clicks the save button, it sends this template to the server with socket.io.
  • templates sent to the server will be saved to hdd with nodejs.

my array template

const MyArray = [
{
div_id:div.id,
div_innerhtml:div.innerHTML,  //<img src=base64...
div_backgroundimage : div.backgroundimage //base64... 
}
]

client-side code

const MyArray=[],SaveBtn = document.queryselector("#save_div");
    
const SendArray = (ARRAY)=>{
    socket.emit("div_data",ARRAY);
}

SaveBtn.onclick = ()=>{
    SendArray(MyArray);
}

server-side code

socket.on("div_data",(data)=>{
    console.log(data)   // function does not react.
    let JSON_DATA = JSON.stringify(data)
    console.log(JSON_DATA)   // function does not react.
});

Is this socket.io error? What should I do or how should I research this issue?

UPDATE

network tab in devtools

for two base64 image : (function work successfully)

enter image description here

for four base64 image : (function does not react)

enter image description here