Gatsby: Gatsby build failing with WebpackError: TypeError: Cannot read property 'map' of undefined

[Developerayo]

While deploying gatsby site to Netlify

$ yarn run build
yarn run v1.13.0
$ rm -rf public && rm -rf .cache && gatsby build
success open and validate gatsby-configs — 0.043 s
success load plugins — 1.595 s
success onPreInit — 24.500 s
success delete html and css files from previous builds — 0.038 s
success initialize cache — 0.273 s
success copy gatsby files — 1.970 s
success onPreBootstrap — 0.022 s
success source and transform nodes — 0.823 s
success building schema — 11.416 s
success createPages — 0.378 s
success createPagesStatefully — 0.207 s
success onPreExtractQueries — 0.002 s
success update schema — 0.447 s
success extract queries from components — 0.470 s
success run graphql queries — 10.306 s — 53/53 5.14 queries/second
success write out page data — 0.024 s
success write out redirect data — 0.004 s
⠈ onPostBootstrapdone generating icons for manifest
success onPostBootstrap — 0.681 s

info bootstrap finished - 80.863 s

success Building production JavaScript and CSS bundles — 34.728 s

error Building static HTML for pages failed

See our docs page on debugging HTML builds for help https://gatsby.app/debug-html

  39 |           )}
  40 |
> 41 |           {posts.map(({ node }) => {
     |                  ^
  42 |             const title = get(node, 'frontmatter.title') || node.fields.slug;
  43 |             return (
  44 |               <article key={node.fields.slug}>


  WebpackError: TypeError: Cannot read property 'map' of undefined

  - blog-index.js:41 BlogIndexTemplate.render
    lib/src/templates/blog-index.js:41:18


  - bootstrap:24 Sa
    lib/webpack/bootstrap:24:1

  - bootstrap:29 a.render
    lib/webpack/bootstrap:29:1


  - bootstrap:40 renderToString
    lib/webpack/bootstrap:40:1

  - static-entry.js:190 Module../.cache/static-entry.js.__webpack_exports__.default
    lib/.cache/static-entry.js:190:18

  - bootstrap:24 Promise
    lib/webpack/bootstrap:24:1


  - gatsby-browser-entry.js:1 Promise._resolveFromExecutor
    lib/.cache/gatsby-browser-entry.js:1:1

  - bootstrap:68 new Promise
    lib/webpack/bootstrap:68:1


  - bootstrap:5 tryCatcher
    lib/webpack/bootstrap:5:1

  - bootstrap:50 MappingPromiseArray._promiseFulfilled
    lib/webpack/bootstrap:50:1

  - api-runner-ssr.js:6 MappingPromiseArray.PromiseArray._iterate
    lib/.cache/api-runner-ssr.js:6:16

  - bootstrap:67 MappingPromiseArray.init
    lib/webpack/bootstrap:67:1


error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

[aderaaij]

It looks like your posts array is undefined. I'd suggest checking if they actually return, and if not, why they're not returning

[pieh]

To add to what @aderaaij said - I would also suggest updating gatsby - we added logging on what page it fails recently, so you could narrow down where this is happening

[Developerayo]

Thanks, it has been fixed.

[Zedonboy]

Hello. During Development it works, but when i build it shows me error