he/him 
[Poll in next tweet] In an ideal world, how would you expect array spread and object spread to deal with nullish values?pic.twitter.com/U3uMrqQU0i
![// Array spread
const mergedArray = [...array1, ...array2];
// → currently throws an exception if e.g. `array2` is `null` or `undefined`
// Object spread
const mergedObject = { ...object1, ...object2 };
// → currently silently ignores `object2` if it’s `null` or `undefined`](https://pbs.twimg.com/media/DT7mnnuXkAMBQQf.png)
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It is based on a long precedence of for..in, utility libraries and Object.assign which has spawned downstream patterns for allowing dealing with optional objects as undefined or null. Would have consequences beyond just this syntax.
There's plenty of places where an object isn't allowed to be optional though. for..of doesn't, neither does `const {} = null;`, likely plenty more too.
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The rationale isn't for consistency, but that the language and ecosystem didn't evolve in isolation. There are therefore certainly reasons to pass null and undefined around as first class values (as opposed to consistently passing objects).
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That's not an argument, but an explanation for why that is a persistent part of the language. If you buy that then, the only argument that matters is whether or not people should be forced to type `{ ...obj || {} }`.
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And the for-of is telling, since spread is based on the iterator protocol. Suggests that the current behavior had a special case hacked in for some reason.
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