serialize-function.js

// In window A:
// ------------

// Store the original functions which will be called remotely from another window
const originalFunctions = {};

// "Serialize" a function by storing it in memory and returning its id
const serializeFunction = (func) => {
    const functionUUID = uuidv4();
    serializedFunctions[functionUUID] = func;
    return functionUUID;
};

// Listen for a post message to call the serialized function from another window
postRobot.on('callSerializedFunction', ({ data ) => {
    const { serializedFunctionUUID, args } = data;
    const originalFunction = originalFunctions[serializedFunctionUUID];
    return originalFunction(...args);       
});

// Create a simple function
const sayHello = (person) => {
    console.log(`Hello ${ person }!`);
};

// Serialize that function down to an id
const serializedSayHelloUUID = serializeFunction(sayHello);

// Now `serializedSayHelloUUID` can be sent over to window B.


// In window B:
// ------------

// "Deserialize" a function by creating a wrapper function which messages the original window
const deserializeFunction = (serializedFunctionUUID) => {
    return (...args) => {
        return postRobot.send(originalWindow, 'callSerializedFunction', {
            serializedFunctionUUID, args
        });
    };
};

// "Deserialize" the sayHello function
const sayHello = deserializeFunction(serializedSayHelloUUID);

// Call the sayHello function
sayHello('world');

// End result: logs 'hello world' in the original window (Window A)