support Symbol objects #29
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index.js
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| const wellKnownSymbols = [ | ||
| Symbol.asyncIterator, | ||
| Symbol.hasInstance, | ||
| Symbol.isConcatSpreadable, | ||
| Symbol.iterator, | ||
| Symbol.match, | ||
| Symbol.matchAll, | ||
| Symbol.replace, | ||
| Symbol.search, | ||
| Symbol.species, | ||
| Symbol.split, | ||
| Symbol.toPrimitive, | ||
| Symbol.toStringTag, | ||
| Symbol.unscopables, | ||
| ].filter (x => typeof x === 'symbol'); |
index.js
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| @@ -114,6 +135,11 @@ const show = x => { | |||
| 'new String (' + show (x.valueOf ()) + ')' : | |||
| JSON.stringify (x); | |||
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| case '[object Symbol]': | |||
| for (const s of wellKnownSymbols) if (s === x) return x.description; | |||
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And then this is just if (wellKnownSymbols.has(x)) return x.description. Performance should remain the same.
| xs.z = 0; | ||
| xs[Symbol ('y')] = 0; | ||
| xs[Symbol ('x')] = 0; | ||
| eq (show (xs), '["foo", "bar", "baz", "z": 0, [Symbol ("x")]: 0, [Symbol ("y")]: 0]'); |
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This representation doesn't evaluate, though. An alternative would be to output Object.assign(["foo", "bar", "baz"], {"z": 0, [Symbol ("x")]: 0, [Symbol ("y")]: 0}) or something. Maybe not worth it?
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You're quite right. This is, though, consistent with existing behaviour:
> show (/x/.exec ('xyz'))
'["x", "groups": undefined, "index": 0, "input": "xyz"]'We could change the representation of non-index properties, but that would be an orthogonal change.
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Sure! Feel free to merge this PR by the way, I just wanted to note it. I'm not sure if it warrants an issue and the consequent work. I can already see the edge cases now, so maybe not open this can. :p
This pull request changes the way Symbol objects are shown:
show (Symbol.iterator)'<object Symbol>''Symbol.iterator'show (Symbol ())'<object Symbol>''Symbol ()'show (Symbol ('x'))'<object Symbol>''Symbol ("x")'show (Symbol.for ('x'))'<object Symbol>''Symbol ("x")':\Additionally,
Array#@@showandObject#@@shownow include symbol properties (seeObject.getOwnPropertySymbols).