1498300 - await does not work in Browser Console

Status: RESOLVED FIXED

(DevTools :: General, defect, P1)

Description

[Michael Cooper [:mythmon]]

Although `await 42;` works as expected in the Web Console, the Browser Toolbox, and the Browser Content Toolbox (printing 42), in the Browser Console it returns the error "SyntaxError: await is only valid in async functions and async generators".

STR:

1. Open the Browser Console (Tools > Web Developer > Browser Console, or Ctrl+Shift+J on Linux)
2. Type "await 42;" and press enter.

Expected:

The console prints "42".

Actual:

The console prints an error.

This might be a dupe of bug 1494726, but I'm not sure where the error happened in that bug.

Comment 1

[Brian Grinstead [:bgrins]]

This isn't a dupe of bug 1494726, it's a separate issue. The problem is that the parser worker is fetched through the toolbox object, and when we are in the Browser Console there's no toolbox available.

I hope that we can expose parser-worker as a separate module that could be accessed from the webconsole (or any other tool that wants to use it) directly.

Nicolas, is there a technical reason the parserService needs to be exposed through the toolbox and couldn't be used by a window like the Browser Console directly? https://searchfox.org/mozilla-central/rev/1ce4e8a5601da8e744ca6eda69e782318afab54d/devtools/client/framework/toolbox.js#691. IOW: do we need the debugger frontend or backend to be available for that to work, or is it independent?

Comment 2

[Nicolas Chevobbe [:nchevobbe]]

We don't need the debugger frontend at all, only the parser worker.
It was put on the toolbox as `parserService` so it could be use across all panels, but as you say, the browser console does not have a toolbox.
I think this could be fixed, I'll have a look soon.

Comment 3

[Nicolas Chevobbe [:nchevobbe]]

Attachment: Bug 1498300 - Add top-level await support to the Browser Console; r=bgrins.

This patch moves the parserService from the toolbox,
which isn't accessible in the case of the Browser Console,
to the console itself.
A lightweight test is added to ensure top-level await is
supported in the browser console.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/21f2d2802b18
Add top-level await support to the Browser Console; r=bgrins.

Comment 5

[Stefan Hindli [:stefan_hindli]]

https://hg.mozilla.org/mozilla-central/rev/21f2d2802b18