WebSockets very, very slow when sending ~1800 characters

I have about 150 LEDs in a strip. I want to change those colors, based on patterns I write externally (in a browser for example). I send the 2D array like this:

[[255, 255, 255], [255, 0, 0], [255, 255, 255]]

and so on from my NodeJS server running the "ws" module as a server. The ESP8266 NodeMCU then connects to the NodeJS server, and waits for it to send the RGB colors for all these LEDs.

The problem occurs when I want to send the RGB codes for all 150 LEDs at once. This takes 1000-1500 milliseconds and it simply queues them up. If I keep it running for 30-60 seconds, then disconnect my NodeJS server, it will keep changing the colors on the LED strip, because it keeps the colors in a queue (because it's too slow?) .

I am running this on a local network and here is my Espruino code:

var esp8266 = require("ESP8266");

function onInit() {
	var ssid = "SSID";
	var wifiOpts = {
		password: "PASSWORD"
	};
	var wifi = require("Wifi");
	wifi.connect(ssid, wifiOpts, function(err) {
		console.log("connected? err=", err, "info=", wifi.getIP());
		var ws = connect();

		ws.on('open', function() {
			console.log("Connected");
		});

		ws.on("message", function(msg) {
			msg = JSON.parse(msg);
			esp8266.neopixelWrite(NodeMCU.D2, msg);
		});
	});
}

function connect() {
	var WebSocket = require("ws");
	var host = "192.168.1.209";
	return new WebSocket(host, {
		path: '/',
		port: 8001,
		protocolVersion: 13,
		origin: 'Espruino',
		keepAlive: 60,
	});
}

save();

Any clue what could be wrong? Is 1800 characters simply too much?