Blueprint: [Core/Toast] Toaster.create() returns null

[casoetan]

Bug report

• __Package version(s)__: @blueprintjs/core": "^1.30.0"
• __Browser and OS versions__: Chrome Canary | MacOS 10.12.6

Steps to reproduce

1. Create a toaster
2. Try to show it
3. Fails as toaster is null

Actual behavior

Toast does not show

Expected behavior

Toast to show

[llorca]

Please provide code examples that repros and exact error messages

[casoetan]

@llorca apologies for the delay.

The defined method

import { Position, Toaster } from '@blueprintjs/core'

export const appNotification = dismissAction => Toaster.create({
  className: 'app-toaster',
  position: Position.TOP,
  onDismiss: () => dismissAction()
})

The component

import React, { Component } from 'react'
import PropTypes from 'prop-types'

import { bindActionCreators } from 'redux'
import { connect } from 'react-redux'

import { appNotification } from './utils/notification'

import Header from './components/Header'
import Footer from './components/Footer'

import { clearNotification } from './actions/app'

class Layout extends Component {
  constructor(props) {
    super(props)
    this.state = {
      toaster: null
    }
  }

  componentDidMount() {
    this.setState = {
      toaster: appNotification(this.props.actions.clearNotification)
    }
  }

  componentWillReceiveProps(nextProps) {
    const { toaster } = this.state
    const { app: { notification } } = this.props
    const { app: { notification: nextNotification } } = nextProps
    if (notification !== nextNotification) {
      toaster && toaster.show(nextNotification)
    }
  }

  render() {
    const { app } = this.props
    return (
      <div>
        <Header app={app} />
        <div>
          {this.props.children}
        </div>
        <Footer />
      </div>
    )
  }
}

const mapStateToProps = state => ({
  app: state.app
})

const mapDispatchToProps = dispatch => ({
  actions: bindActionCreators({ clearNotification }, dispatch)
})

Layout.propTypes = {
  children: PropTypes.any.isRequired,
  app: PropTypes.object.isRequired,
  actions: PropTypes.shape({
    clearNotification: PropTypes.func
  })
}

export default connect(mapStateToProps, mapDispatchToProps)(Layout)

appNotification is always null, o calling .show(message) on it breaks ...

cannot call method show on null

[AlexLandau]

this.setState = { should be this.setState({, no?

[cmslewis]

^ @casoetan - yes, try this and let us know if it fixes your issue.

[giladgray]

@casoetan there are a number of bugs in your code, including the setState assignment mentioned above. The most glaring is, of course, that you're not using the Toaster API correctly:
Toaster.create() returns a toaster _instance_ with a show method. It is this show method which accepts onDismiss, so you're passing that handler in the wrong place.

The expected usage is something like this:

1. Create a Toaster instance using Toaster.create() (typically one instance per position).
   
   
   
   • I like defining this instance in a separate module like common/toaster.ts so any component can simply import it and profit 💸
     
     js export const TopToaster = Toaster.create({ position: TOP, ... })
   
   
2. Call instance.show({ ...props, onDismiss }) to show a toast in that Toaster.
   ```js
   import { TopToaster } from "../path/to/common/toaster";

// later, in response to user event:
TopToaster.show({ ...props, onDismiss: this.handleDismiss })
```

Hope this helps! Please refactor your code and let us know if you can get it working.

[giladgray]

Oh it's also worth noting that calling Toaster.create inside a component lifecycle method can actually return null (and it _definitely_ returns null in React 16): https://reactjs.org/blog/2017/09/26/react-v16.0.html#breaking-changes (2nd bullet)

_Edit:_ All this to support my proposal of defining a Toaster at initialization time (i.e., import) instead of at render() or mount time.

[casoetan]

@AlexLandau the set state was obviously from scratching my head for over 2 days trying to get what worked on React 15 to work on React 16.

@giladgray you are quite right. In React 16, this would always return null. #https://github.com/facebook/react/issues/10309#issuecomment-318433235.

The Toaster does not work with SSR as it depends on the dom, reason I'm instantiating in ComponentDidMount.

[casoetan]

@AlexLandau the set state was obviously from scratching my head for over 2 days trying to get what worked on React 15 to work on React 16.

@giladgray you are quite right. In React 16, this would always return null. #https://github.com/facebook/react/issues/10309#issuecomment-318433235.

The Toaster does not work with SSR as it depends on the dom, reason I'm instantiating in ComponentDidMount.

[casoetan]

Solved with https://github.com/palantir/blueprint/issues/1205

export const Toast = (typeof window !== 'undefined')
   ? Toaster.create({
     className: 'my-toaster',
     position: Position.BOTTOM_RIGHT
   })
  : null

[ConneXNL]

I am using a DIC for the toaster, so it calls it whenever its used for the first time.

In this case its also returning null.