[Firefox] Firefox errors on the markdown's unicode regular expression for word definitions

[mjbvz]

Repo

1. Using firefox
2. Open a markdown file

Bug
In dev tools, see:

invalid identity escape in regular expression: _reviveRegExp@http://localhost:9888/static/out/vs/workbench/api/browser/mainThreadLanguageFeatures.js:460:20
$setLanguageConfiguration@http://localhost:9888/static/out/vs/workbench/api/browser/mainThreadLanguageFeatures.js:485:88
_doInvokeHandler@http://localhost:9888/static/out/vs/workbench/services/extensions/common/rpcProtocol.js:331:27
_invokeHandler@http://localhost:9888/static/out/vs/workbench/services/extensions/common/rpcProtocol.js:316:45
_receiveRequest@http://localhost:9888/static/out/vs/workbench/services/extensions/common/rpcProtocol.js:243:32
_receiveOneMessage@http://localhost:9888/static/out/vs/workbench/services/extensions/common/rpcProtocol.js:171:26
RPCProtocol/<@http://localhost:9888/static/out/vs/workbench/services/extensions/common/rpcProtocol.js:61:52
fire@http://localhost:9888/static/out/vs/base/common/event.js:458:38

[rebornix]

It's already being tracked in Firefox bugzilla as it doesn't implement RegExp Unicode Property Escapes yet https://bugzilla.mozilla.org/show_bug.cgi?id=1361876

vscode/src/vs/base/common/strings.ts

Lines 239 to 244 in 9b34464

	export function regExpFlags(regexp: RegExp): string {
	return (regexp.global ? 'g' : '')
	+ (regexp.ignoreCase ? 'i' : '')
	+ (regexp.multiline ? 'm' : '')
	+ ((regexp as any).unicode ? 'u' : '');
	}

I'm not a fan of having special logic for Firefox to stop unicode escaping and creating regex without u flag. The error is thrown from word pattern regex parsing and as I didn't see any misbehavior of word related operations in Markdown files, I'll recommend to put this issue in backlog and ask for Firefox to catch up @mjbvz .

[connorshea]

Looks like this is coming in Firefox 78 :) https://bugzilla.mozilla.org/show_bug.cgi?id=1361876#c16

[mjbvz]

Confirmed this is fixed in the latest Firefox release