Gatsby: The Starter Library category page is not displayed.

[kawamataryo]

Description

The Starter Library category page is not displayed.

Steps to reproduce

1. See Starters page
   https://www.gatsbyjs.org/starters?v=2

2. Click on any category list
   (ex
   https://www.gatsbyjs.org/starters?c=CMS%3AContentful&v=2

Expected result

Displayed category page.

Actual result

Displayed white page, and show this errors in console.

react-dom.production.min.js:4684 TypeError: Cannot read property 'tags' of undefined
    at filtered-starters.js:280
    at Array.filter (<anonymous>)
    at filtered-starters.js:279
    at n.render (filtered-starters.js:93)
    at qi (react-dom.production.min.js:4289)
    at Ki (react-dom.production.min.js:4280)
    at So (react-dom.production.min.js:6722)
    at hu (react-dom.production.min.js:5696)
    at pu (react-dom.production.min.js:5685)
    at au (react-dom.production.min.js:5441)

Environment

Mac OS Catalina 10.15.3

Checked browser.

• Safari 13.05
• Chrome 80.0.3987.122

[LesleyLai]

Same issue with showcases. Some search find #21792 potentially causes the problem.

[Vincent440]

Showcase page does not display after clicking any items in the search pane. This is the error I am getting

16:52:39.083 ReferenceError: "edge is not defined"
    a filtered-showcase.js:29
    render filtered-showcase.js:23
    React 7
    unstable_runWithPriority scheduler.production.min.js:274
    React 19
    UxWs production-app.js:154
    setTimeout handler*MMVs/e.exports</< ready.js:32
    UxWs production-app.js:153
react-dom.production.min.js:4684:12
    React 5
    unstable_runWithPriority scheduler.production.min.js:274
    React 4
    unstable_runWithPriority scheduler.production.min.js:274
    React 19
    UxWs production-app.js:154
    (Async: setTimeout handler)
    exports ready.js:32
    UxWs production-app.js:153
16:52:39.084 ReferenceError: edge is not defined filtered-showcase.js:29:30
    a filtered-showcase.js:29
    reduce self-hosted:303
    render filtered-showcase.js:23
    React 6
    au self-hosted:920
    ql React
    unstable_runWithPriority scheduler.production.min.js:274
    React 5
    _n self-hosted:977
    React 14
    UxWs production-app.js:154
    (Async: setTimeout handler)
    exports ready.js:32
    UxWs production-app.js:153
16:52:39.084 ReferenceError: "edge is not defined"
    a filtered-showcase.js:29
    render filtered-showcase.js:23
    React 7
    unstable_runWithPriority scheduler.production.min.js:274
    React 19
    UxWs production-app.js:154
    setTimeout handler*MMVs/e.exports</< ready.js:32
    UxWs production-app.js:153
react-dom.production.min.js:4684:12
    React 5
    unstable_runWithPriority scheduler.production.min.js:274
    React 4
    unstable_runWithPriority scheduler.production.min.js:274
    React 19
    UxWs production-app.js:154
    (Async: setTimeout handler)
    exports ready.js:32
    UxWs production-app.js:153

[kawamataryo]

I sent a pull request #21876.