withTracker with async code

[mfeuermann]

Hi developers,

I wanted to ask if it is possible to use the withTracker function call in combination with the asynchronous call that will be introduced in Meteor 3.0

I have a large application where I use the container architecture with React components
Example of container...

`import { withTracker } from 'meteor/react-meteor-data';
import {useDeps} from '@beisen/storybook-mantra-core';
import _ from 'lodash';

import locales from '../components/locales.jsx';
import {Locales} from '/lib/collections';

export const depsMapper = (context) => ({
context: () => context
});

const localesWT = withTracker(({context, id}) => {

const {Log, LocalState} = context();

let localesArray = Locales.find({language: 'en'}).fetch();

return {
localesArray
};
})(locales);

export default useDeps(depsMapper)(localesWT);
`

In the withTracker function I would like to call asynchronously however currently the content is rendered and does not wait for await...

Can we expect the withTracker function to be modified for use with Meteor.callAsync ?

Thanks

[Grubba27]

Currently, the way to go for using the async tracker is what we have documented in the react-meteor-data docs, which uses the Suspense API.

The following code was taken from the docs:

import { useTracker } from 'meteor/react-meteor-data/suspense'
import { useSubscribe } from 'meteor/react-meteor-data/suspense'

function Tasks() { // this component will suspend
  useSubscribe("tasks");
  const { username } = useTracker("user", () => Meteor.user())  // Meteor.user() is async meteor 3.0
  const tasksByUser = useTracker("tasksByUser", () =>
          TasksCollection.find({username}, { sort: { createdAt: -1 } }).fetchAsync()) // async call
  );


  // render the tasks
}

[mfeuermann]

Thank you for the information, is there also a suspension implementation planned for withTracker ?
The thing is that we use container pattern in our application... The question is whether it is planned to redesign it in the future
Thanks for info
Marek

[Grubba27]

Got! I have not talked about having a suspense version of withTracker with @radekmie, but I think we can discuss this. Will bring it in our next meeting.
Will keep you updated

[mfeuermann]

OK thank you, by the way I made a minor adjustment and it seems to work fine. Unfortunately I don't know TS so it's in JS.
But it would be great if it could be delivered directly to the code.
Thank you, I appreciate your work.

`import React, { forwardRef, memo } from 'react';
import { useTracker } from 'meteor/react-meteor-data/suspense';

export const withTracker = (options) => {
return (Component) => {
const getMeteorData = typeof options === 'function' ?
options :
options.getMeteorData;

const WithTracker = forwardRef((props, ref) => {
  const data = useTracker('', () => getMeteorData(props) || {});
  // const data = {};
  return (
    <Component ref={ref} {...props} {...data} />
  );
});

const { pure = true } = options;
return pure ? memo(WithTracker) : WithTracker;

};
};
`