TypeError: Cannot read property 'length' of undefined

[joelgrodriguez]

I just installed a fresh instance of WP and the starter.

The home page pulls up no problem but...

For some reason when I click on a post I am getting this error.

Server Error
TypeError: Cannot read property 'length' of undefined

`
147 |
148 | const { categories, postId } = post;

149 | const category = categories.length && categories[0];
| ^
150 | let { name, slug } = category;
151 |
152 | return {`

I have not added anything else to the starter (other than the graphql endpoint).
I have not added any posts new posts.
I added only one additional category for testing.

Is there a step I am missing?

Here is the WP install: http://newtechmachinery.kinsta.cloud/

thanks

[colbyfayock]

hey @joelgrodriguez i was able to reproduce, thats relaly strange

What results do you get when you run this query inside of the GraphiQL IDE?

{
  postBy(slug: "hello-world") {
    id
    title
    slug
  }
}

the issue is for some reason the query isn't finding the post by it's slug

[joelgrodriguez]

This was returned:

{ "data": { "postBy": null }, "extensions": { "debug": [ { "type": "DEBUG_LOGS_INACTIVE", "message": "GraphQL Debug logging is not active. To see debug logs, GRAPHQL_DEBUG must be enabled." } ] } }

[colbyfayock]

@doingandlearning have you seen something like this before? any ideas?

the post metadata coming from the homepage has the hello-world slug

[
  {
    __typename: 'Post',
    author: {
      __typename: 'User',
      avatar: [Object],
      id: 'dXNlcjox',
      name: 'jrodriguez',
      slug: 'jrodriguez'
    },
    id: 'cG9zdDox',
    categories: [ [Object], [Object] ],
    content: '\n' +
      '<p>Welcome to WordPress. This is your first post. Edit or delete it, then start writing!</p>\n',
    date: '2021-04-30T02:13:28',
    excerpt: '<p>Welcome to WordPress. This is your first post. Edit or delete it, then start writing!</p>\n',
    featuredImage: null,
    modified: '2021-04-30 12:58:57',
    modifiedGmt: '2021-04-30T12:58:57',
    postId: 1,
    title: 'Hello world!',
    slug: 'hello-world',
    isSticky: false
  }
]

[joelgrodriguez]

I'm thinking it may have something to do with Kinsta?

I just tested this on local install using Local by Flywheel and I am able to load the post with no errors.

[doingandlearning]

This is interesting. I think there was some talk about deprecating the by functions like postBy. It does indeed look like that's happened on your instance. This could be a WP version or WPGraphQL version.

To fix this in our code, we'd move from using postBy to using post. The new query would look like this:

{
  post(id: "hello-world", type: SLUG) {
    id
    title
    slug
  }
}

I'll send a message on the WPGraphQL Slack group about it to confirm if a new change has been made.

I note that when I use this new query on your instance @joelgrodriguez I get the data back as expected.

[joelgrodriguez]

I was able to get the expected data back but with a modified query from yours @doingandlearning :

query MyQuery { post(id: "hello-world", idType: SLUG) { id title slug } }

The query provided above returned an error for me.

Thanks

[colbyfayock]

thanks for the heads up both of you, will get that updated to the new query format unless one of you wanna put in a PR :)

[doingandlearning]

Very happy to do this.

Confirmed with the WPGraphQL team that this was an issue.

[colbyfayock]

Fixed via #156