Unable to get value synchronously

[monsterooo]

Hi @Tyriar

I wrote some data using term.writeln. At the same time, I can't get the value I just set using term._core.buffer. But when I set a timer, everything works fine setTimeout(getBuffer, 3000);

I tested the demo used：
https://codesandbox.io/embed/elated-davinci-mue6q

I am very confused. Do you know why? 🤔

thank you very much!

[monsterooo]

xterm.js/src/Terminal.ts

Line 157 in bc5e1e6

public writeBuffer: string[];

term._core.writeBuffer Is it a reliable way to use it ？

[Tyriar]

We've been discussing a method of knowing when the data was written for a while, I don't think there's an issue for it yet so let's track it in here.

#2362 has the callback for write but we might merge it in with a smaller PR before that.

[jerch]

@monsterooo

I am very confused. Do you know why?

write and writeln are async methods, they get not immediately processed. The reason for this is the output, we have to process incomming data in chunks to allow the renderer to update the viewport in between.

term._core.writeBuffer Is it a reliable way to use it ？

You should not rely on term._core.writeBuffer - its not exposed via API thus may change over time. Furthermore its the buffer for incomming data, the terminal has not yet dealt with that data.

As @Tyriar wrote the plan is to add a callback to write methods (nodejs style) that gets called once the chunk was processed by the parser. With this you can promisify your code later on:

...
await new Promise(resolve => term.write('some string data', resolve));
doSomething(); // executed after the chunk was processed
...