blakeembrey/javascript-stringify

Repeated references in Maps & Sets produce broken output

Opened this issue ยท 3 comments

Briefly, this happens:

const obj = {}
const map = new Map([['a', obj], ['b', obj]])
const ok = stringify(map)
// "new Map([['a',{}],['b',{}]])"
const bad = stringify(map, null, null, { references: true })
// "(function(){var x=new Map([['a',{}],['b',undefined]]);x[1][1]=x[0][1];return x;}())"
eval(bad)
// Uncaught TypeError: Cannot read property '1' of undefined

The problem here is that the object type isn't tracked, and therefore isn't taken into account by stringifyPath. The . and [] forms work fine for arrays and objects, but don't for Maps and Sets. The path in those cases is referring to the Array.from() constructions, rather than the resulting objects.

That makes sense, ES6 data structures were a more recent addition that I didn't think through entirely. I'll try and fix it over the weekend, thanks for the report!

Would a PR on this be welcome? Not promising anything, mind...

Sorry for the delay, PRs are always welcome on any repo I maintain ๐Ÿ˜„ I just always get busier than I expect, so I'm sorry ๐Ÿ™