pm.collectionVariables.set/get behaves differently in Postman app than in Newton/Postman CLI

Ask the Experts and Postman Tips
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Hi y’all

I have this in a post-response of a request:

const metadata = pm.response.json()[0].metadata; // either `null` or a string
pm.collectionVariables.set('metadata', metadata)

I use this variable to conditionally skip the next request; I have this in its pre-request script:

const metadata = pm.collectionVariables.get('metadata');

if (metadata === null) {
    console.warn('WARN: /seatmap execution skipped: metadata was null')
    pm.execution.skipRequest();
}

this works like a charm in the Postman app (windows 11), but when I tried the same collection with Newman, the second request was being executed.

After a little digging, I discovered that in the Postman app, the metadata variable was saved and then recovered as a null object, but in Newman (and Postman CLI) it was either saved or recovered as a "null" string!

I resolved this issue by comparing metadata with "null" instead, so it’s not a problem for me anymore, but it seems like a bug, so I wanted to report it.

@danny-dainton