Bookmarked just because I like the name.... ;-D
So all JSON is valid (modern) JavaScript. [1]
Is RON valid Rust?
The article leads with an incorrect statement. JSON is now a subset of JavaScript: https://github.com/tc39/proposal-json-superset
JSON is a syntactic subset of Javascript in ES2019 [1].
That bit of incompatibility will be going away when this proposal is implemented, however:
> For instance, RFC 8259 mentions that a design goal of JSON was to be "a subset of JavaScript", but it's actually not.
Actually, it's really close https://github.com/tc39/proposal-json-superset
This is a stage 3 proposal likely to make it to the next version of the spec. At which point JSON would truly be a subset of JavaScript.
Even that's not technically true. You can represent things in JSON that can't be represented in ES object literals. There's a proposal in Stage 3 to fix that though: https://github.com/tc39/proposal-json-superset