Print

The Print API lets you intercept all standard log output coming out of the Unity Module — both internal information messages from the loader and runtime, and Debug.Log calls from your C# code — before they reach the browser console.

Type Definition

Type Definition

function print(message: string): void;

Implementation

By default, Unity routes its standard output through console.log. When a print handler is provided to the Unity Config, Unity will call your handler instead of writing to the console directly. This is useful for forwarding Unity logs into a custom logger, dev tools panel, telemetry sink, or in-app debug overlay.

Both internal Unity messages (loader progress, framework diagnostics) and your own Debug.Log calls flow through this handler.

info

The handler is captured once during initialisation and passed to createUnityInstance. Changing the function reference after the Unity Instance has booted will not have any effect, so prefer a stable reference (for example via useCallback or a module-scope function).

caution

The handler replaces the default console output. If you still want messages in the browser console, call console.log from inside your handler.

Example Usage

A basic implementation could look something like this. In the following example we'll forward every Unity log message to both the console and a telemetry function.

App.jsx

import React from "react";
import { Unity, useUnityContext } from "react-unity-webgl";

function App() {
  function handlePrint(message) {
    console.log("[Unity]", message);
    telemetry.capture({ severity: "info", message });
  }

  const { unityProvider } = useUnityContext({
    loaderUrl: "build/myunityapp.loader.js",
    dataUrl: "build/myunityapp.data",
    frameworkUrl: "build/myunityapp.framework.js",
    codeUrl: "build/myunityapp.wasm",
    print: handlePrint,
  });

  return <Unity unityProvider={unityProvider} />;
}