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yaml: add option for using Maps instead of objects for mappings #7283
Description
Is your feature request related to a problem? Please describe.
JS objects are limited to string and symbol keys. If one needs different key types, there's Map.
YAML is capable of mappings that have non-string keys. It's a niche use case, sure, but one I have! I'm using number keys to map events that trigger at certain milestones in my data model:
milestones:
3: A3
6: D4
9: G3Right now, I have to re-parse the numbers and convert it into a Map. An easy one-liner, but unnecessary IMO!
Another ugly use case that I don't personally have, but I guess is valid
I hope one never does this, but...
mapping:
2: technically
"2": valid 😔Describe the solution you'd like
Add a boolean option to ParseOptions, useMaps, defaulting to false.
Describe alternatives you've considered
Just putting up with converting the objects 🤷
Activity
tomas-zijdemans commentedon Aug 16, 2026
Opened #7290 implementing this behind a
useMapsboolean on the unstableparse(), per the request.Two adjacent questions for maintainers that I deliberately kept out of that PR:
stringify(new Map([["a", 1]]))silently emits{}today, which loses data. feat(yaml/unstable): add useMaps option to parse mappings into Maps #7290 fixes this only in the unstablestringify(). Should the stable one learn the same representation (a behavior change), or throwTypeErrorlike other unrepresentable values do?"[object Object]"key coercion into aYamlSyntaxErrorthat namesuseMaps, instead of silently mangling non-string keys?