JavaScript error in Block Editor when ClassifAI has not been set up correctly

[junaidbhura]

Describe the bug
A JavaScript error is fired in the Block Editor when ClassifAI has not been set up. This prevents a post from being saved. This occurs because ClassifAI looks for a meta value without checking for its existence.

The JavaScript error says:

Uncaught TypeError: Cannot ready property '_classifai_error' of undefined

Steps to Reproduce

1. Install and activate ClassifAI
2. Do not enter any details
3. Create a post in the block editor and save, ideally one with post meta boxes
4. A JavaScript error is fired (Screenshot below)

Expected behavior
Post saves without any JavaScript errors.

Screenshots

Environment information

• Device: Macbook Pro
• OS: MacOS 11.4
• Browser and version: Brave (Chromium 91)
• WordPress version: 5.7.2

Additional context

[dinhtungdu]

@junaidbhura I can't reproduce the issue on WP 5.7.2, new multisite with unconfigured ClassifAI (develop branch). Watching the value of meta, it returns an empty array in my test, which means that the variable is not undefined. Can you give me more detailed instructions?

I agree with your additional check added in #286, we should always check the existence of variable first before using them. But I want to reproduce the issue first before merging your PR.

[junaidbhura]

Hey @dinhtungdu do you think you could try it on a post type that is not configured to work with ClassifAI?

[dinhtungdu]

@junaidbhura the same thing happens for unsupported post type, they value of meta always is [].

[junaidbhura]

Hey @dinhtungdu I've reached out to you on DM with some additional context!

[dinhtungdu]

Thanks for the clarification! I approved the PR.

[junaidbhura]

Thanks @dinhtungdu !