語系支援
https://docs.microsoft.com/en-us/bot-framework/nodejs/bot-builder-nodejs-localization

Determine the locale by prompting the user

bot.dialog('/localePicker', [
    function (session) {
        // Prompt the user to select their preferred locale
        builder.Prompts.choice(session, "What's your preferred language?", 'English|Español|Italiano');
    },
    function (session, results) {
        // Update preferred locale
        var locale;
        switch (results.response.entity) {
            case 'English':
                locale = 'en';
                break;
            case 'Español':
                locale = 'es';
                break;
            case 'Italiano':
                locale = 'it';
                break;
        }
        session.preferredLocale(locale, function (err) {
            if (!err) {
                // Locale files loaded
                session.endDialog(`Your preferred language is now ${results.response.entity}`);
            } else {
                // Problem loading the selected locale
                session.error(err);
            }
        });
    }
]);

去年得再一開始就設定好，不過目前可以在對話裡切換語系了

Determine the locale by using analytics

因為實現了在對話中就可以切換語系，故可以將 message 丟給 text analytic api 之類，讓其判斷語系後，我在於程式中做切換。

YES ! 終於　明天開始　line builder 重構２版吧！