Define variable global not local - node.js

Question

I have some issues to use a global variable in my node.js app.
I use:
app.locals.isTestCafeRunning = false;
I think the problem here is locals, I think this variable is only valid inside the browser session, not inside the global app.
I want to use this variable in the main route:
app.get('/', function(req, res) {
async function getListData(){
var myListOptions = "";
var myListText = "";
arrayTestcaseData = await getMongojson();
/*code cut*/
var inPlaceButton = "";
if(req.app.locals.isTestCafeRunning===false){
inPlaceButton = "<button id=\"myButton\">Testrun starten</button>";
}else{
inPlaceButton = "<strong>Clipcafe in Benutzung!</strong>";
}
myHtmlCode = myHtmlCode.replace("%%BUTTON%%",inPlaceButton);
res.send(myHtmlCode);
}
getListData();
});
I want to fill the variable in
app.post('/clicked', (req, res) => {
//Function start Testcafe?
createTestCafe('localhost', 1337, 1338)
.then(tc => {
testcafe = tc;
const runner = testcafe.createRunner();
req.app.locals.isTestCafeRunning = true;
inputStore.clLogin = req.body.name;
inputStore.clPassword = req.body.pass;
inputStore.metaFolder = '19233456';
inputStore.metaUrl = req.body.channel;
return runner
.src(['tests/temp.js'])
.browsers(myBrowser)
//.browsers('browserstack:Chrome')
.screenshots('allure/screenshots/', true)
.reporter('allure')
.run();
})
.then(failedCount => {
req.app.locals.isTestCafeRunning = false;
console.log('Tests failed: ' + failedCount);
testcafe.close();
startReportGenerator();
res.sendStatus(201);
});
});
But I want to have this global not local vor all users, so if user 1 starts TestCafe, user 2 will only see "In use".