weird bug with `import { Template } from 'meteor/templating'`

[hacknlove]

import { Template } from 'meteor/templating' stop working since last meteor update

I had a working meteor application.

I updated to meteor 1.6 and then Template was undefined wherever js file with import { Template } from 'meteor/templating'

If I remove import { Template } from 'meteor/templating' everything runs fine with Template from global space.

If I remove ostrio:flow-router-extra I can import { Template } from 'meteor/templating' again.

The next meteor app reproduces the bug templating.tar.gz

[mikhail-shishov]

Hello @hacknlove ,

Which version of flow-router-extra do you use? Also, have you installed templating package as it was advised in this comment?

//cc @dr-dimitru

[coagmano]

I had the same issue, removing ostrio:flow-router-extra fixes the error (but makes app unusable)

Tried adding, removing & adding templating and blaze-html-templates with no effect

Reinstalling to get the version number (3.4.5) seems to have fixed it 🤷‍♂️

[coagmano]

I have a suspicion that dropping the dependency on templating and blaze confused Meteor's bundler, so I've added a PR #44 to add them back in as weak dependencies.

[dr-dimitru]

Hmm, I'll require minimal reproduction, as I've tested it before publishing, and now it works well too.

Btw weak dependency looks fine too.

Could you please check Templating package placed above flow-router-extra in .meteor/packages file??

[coagmano]

Just tested with @hacknlove's repro and it has the error, which is fixed by including templating above ostrio:flow-router-extra in packages and also fixed by adding the weak dependencies.

Which confirms my suspicions of Meteor not making templating available to flow-router.

In addition, using require to test if templating is available seems to cause require to "forget" what templating is...

I then tried replacing the require + try/catch:

try {
  Blaze    = require('meteor/blaze').Blaze;
  Template = require('meteor/templating').Template;
} catch (e) {
  // we're good
}

with:

if (Package['templating'] && Package['blaze']) {
  Blaze    = Package['blaze'].Blaze;
  Template = Package['templating'].Template;
}

Which prevents require from "forgetting" templating. (and is the way mentioned quietly in the docs: https://docs.meteor.com/api/packagejs.html#PackageAPI-use)

I've added the change from require to Package in the PR as well

[dr-dimitru]

Reopened until new release is published

[dr-dimitru]

@coagmano I didn't get this one:

In addition, using require to test if templating is available seems to cause require to "forget" what templating is...

How require makes templating be forgotten?

[coagmano]

I have no idea, it seems to be a bug in require's implementation 🤷‍♂️ Don't know if it's meteor's implementation or part of commonjs

Because really, when require throws an error for a package that isn't available to flow-router-extra, it shouldn't then make that package not available to anything else ever...

[dr-dimitru]

@coagmano thank you for update, this what I was looking for:

make that package not available to anything else ever

[dr-dimitru]

@coagmano thank you for the fix. @hacknlove thank you for rising this question up. Please update to the latest release, this issue should be solved now - v3.4.6