Feature request: Programatic navigation

[josephg]

I've ended up using this action to navigate between pages:

  effects: {
    navigate: (action, state, send) => {
      send('app:location', {location: action.location});
      window.history.pushState({}, null, action.location);
    }
  }

It'd be nice if there was an officially recommended way to do it. (This or something else.)

[timwis]

Hey @josephg, we were just talking about this (see #21). It looks like the best way may be to use the native DOM API (window.location.hash = 'foo'). For browser history, I can't member if it's window.location.url or pushState as you have above. But the point is, adjusting those triggers the internal router. And the nice thing about this is that you don't have to memorize a new framework-specific way to change the page/URL. How's that sound?

[josephg]

If we can pull it off, perfect. I tried that first hoping it would automatically work. Thanks!

[yoshuawuyts]

@josephg Did you end up resolving this - can this be closed?

[josephg]

Well if thats the intended behaviour, it doesn't work yet:

const choo = require('choo');
const app = choo();

const nav = (url) => {
  console.log('nav to', url);
  window.history.pushState(null, null, url);
}

app.router((route) => [
  route('/', (params, state, send) => choo.view`
    <button onclick=${() => nav('/foo')}>Nav</button>
  `),

  route('/foo', (params, state, send) => choo.view`<h1>Somewhere else</h1>`)
]);

document.body.appendChild(app.start());

... The button changes the URL but the new route isn't rendered.

[timwis]

window.location.href = '/foo' works for me with your code

[josephg]

@timwis: That forces an unnecessary full page re-render, which I'm trying to avoid.

[josephg]

Also @yoshuawuyts: Taking a look at the browser's API, I don't think there's any way for the framework to find out when pushState / replaceState is called.

From MDN:

Note that just calling history.pushState() or history.replaceState() won't trigger a popstate event. The popstate event is only triggered by doing a browser action such as clicking on the back button (or calling history.back() in JavaScript).

So for simple navigation, pushState will need to be wrapped somewhere. It can happen in the app - using something like the code I posted at the top of this issue. Or it can be in choo itself.

[yoshuawuyts]

@josephg you're right - labelling this a bug; we should fix this

[MattMcFarland]

So what would the appropriate fix be?

If someone changes the window.location, are you saying we need to let choo know somehow? I would prefer that this is done manually, or at least by somehow setting up a subscription to the window.

At anyrate, can someone explain what the problem / intended result should be? I'm not clear on the issue, the original post actually seems like a reasonable approach to me and it doesnt look like a bug. So I must be reading this wrong.

[mantoni]

@MattMcFarland It's not a bug. It's a feature request to make it possible to change the location with a single API call (e.g. send('app:location', {location: action.location});) without the need to manually fiddle with pushState. Does that answer your question?

[MattMcFarland]

@mantoni Yes thank you!

Is this a feature we are going to add? If so I could work on this providing nobody else is. I"m just looking for something to do :)

[mantoni]

@MattMcFarland I saw that @yoshuawuyts was looking into it recently and concluded that this would be a breaking change (see his last comment here).

[yoshuawuyts]

[oops mispasted comment, moved it to https://github.com//issues/65#issuecomment-236914727]

[yoshuawuyts]

Yup I think this should all work now in v4 - closing! 😁