How To Write Reusable and Testable Code with Microsoft Bot Framework

app.js

const bot = new builder.UniversalBot(connector);
bot.dialog(‘/’, [
    (session, args, next) => {
        if (session.userData.languageSet) {
            next();
        } else {
            session.beginDialog(‘welcome:/pickLocale’);
        }
    }, 
    ...
]);
            
bot.library(require('./dialogs/welcome'));

Hi

A little mistake in your code :
session.beginDialog(‘welcome:/pickLocale’);

Replace by
session.beginDialog(‘welcome:pickLocale’);

To invoke dialogs within your library bots will need to call session.beginDialog() with a fully qualified dialog id in the form of ':'. You'll typically hide this from the devloper by exposing a function from their module that starts the dialog for them. So calling something like myLib.someDialog(session, { arg: '' }); would end up calling session.beginDialog('myLib:someDialog', args); under the covers.

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