How to add --unhandled-rejections=strict

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1

Hi! Is it possible to pass the --unhandled-rejections=strict flag to Node during the build? I want the build to fail when there’s an unhandled promise rejection.

2

You can set NPM_FLAGS environment variable: Build environment variables | Netlify Docs

3

Just to confirm: does this affect all Node scripts, not just npm install? The docs seem to say it’s only for npm install.

I would need the flag for Gatsby’s build process (npm run build)

4

I haven’t tried it but yes, according to the docs, it seems to work only for install command.

I think you can pass the flag in the command itself like, npm run build --unhandled-rejections=strict? Have you tried it?

5

Actually, no I haven’t tried modifying the build script itself. Too obvious :man_facepalming: :laughing:
Thanks again, I’ll try that!

6

Hmm, no luck so far. Not sure I’ve managed to put the CLI parameter in the right place, but it seemed to work locally at least.

Here’s a snippet of a recent failed build (full log), which Netlify thought was okay and tried to deploy:

1:24:13 PM: (node:1288) UnhandledPromiseRejectionWarning: Error: Command failed: DOCS_CONTENT_ROOT=../../ npx --unhandled-rejections=strict gatsby build --prefix-paths
1:24:13 PM:     at checkExecSyncError (child_process.js:630:11)
1:24:13 PM:     at execSync (child_process.js:666:15)
1:24:13 PM:     at /opt/build/repo/scripts/build-preview.js:50:3
1:24:13 PM:     at processTicksAndRejections (internal/process/task_queues.js:97:5)
1:24:13 PM: (node:1288) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
1:24:13 PM: (node:1288) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
1:24:13 PM: ​
1:24:13 PM: (build.command completed in 4m 44.8s)
1:24:13 PM: ​
1:24:13 PM: ────────────────────────────────────────────────────────────────
1:24:13 PM:   2. Deploy site                                                
1:24:13 PM: ────────────────────────────────────────────────────────────────
1:24:13 PM: ​
1:24:13 PM: Starting to deploy site from 'scripts/docs-app/public'
1:24:13 PM: Creating deploy tree 
1:24:13 PM: Creating deploy upload records
1:24:13 PM: 0 new files to upload
1:24:13 PM: 0 new functions to upload
1:24:13 PM: Site deploy was successfully initiated
7

I think I’ll open a new topic, with a more descriptive title, describing the problem, not a potential solution, and link back here.