Working with conversation state

Stateless conversation is annoying. Noone wants to repeat, what was said. So each user has own state object.

Using the state in navigation

Request object contains .state attribute, which represents state before the event, Responder updates new state with Object.assign() approach.

const { Router } = require('wingbot');
const bot = new Router();

bot.use('/rename', (req, res) => {
    res.text('So, how will you call me?')
        .expected('setName');
});

bot.use('/setName', (req, res) => {
    const name = req.text();

    res.text(`Now, I'am ${name}.`)
        .setState({ name });
});

bot.use((req, res) => {
    const { name } = req.state;
    if (name) {
        res.text(`Call me ${name}, ok?`, {
            rename: 'It\'s not ok'
        });
    } else {
        res.text('I have no name, give me one!')
            .expected('setName');
    }
});

module.exports = bot;

This example makes conversation flow like this:

*-----------------------------------*
|                             Hello |
| I have no name, give me one!      |
|                                   |
|                            Albert |
| Now, I'am Albert.                 |
|                                   |
|                             Hello |
| Call me Albert, ok?               |
|                                   |
|                       It's not ok |
| So, how will you call me?         |
|                                   |
|                            Alfred |
| Now, I'am Alfred.                 |
*-----------------------------------*

Reading and modifiing user state

It's good to know, that request state is not modified, when res.setState() is called. It will be modified after dispatching process.

const { Router } = require('wingbot');
const bot = new Router();

bot.use((req, res) => {
    // let's give two options to user
    if (req.state.odd) {
        res.setState({ odd: false });
        // still req.state.odd === true
        this.text('Odd');
    } else {
        res.setState({ odd: true });
        // still req.state.odd === false || req.state.odd === undefined
        this.text('Even');
    }
});

module.exports = bot;

It's better to avoid using "default state", because when you need to change default state in future updates, you should also migrate current users states to new structure.

Default state properties

beforeLastInteraction is useful property, which makes bot able to go back to the last interaction using postBack(req.state.beforeLastInteraction)