v-for: Difference between using index and not providing a key?

[xsjcTony]

So what's the difference between the default algorithm for v-for when no key is provided, and when index is used as the key?

[edison1105]

this is documented see https://vuejs.org/api/built-in-special-attributes.html#key

[xsjcTony]

Yeah I'm aware vue has a default algorithm to handle things when there's no key provided, but my question is which is better? (default vs index)

[edison1105]

Providing a key is better.
Edit:
Providing a good key is better.

[xsjcTony]

It's actually surprising to me that if you are true, that index is better than the default algorithm, since index key is generally considered bad (unless it's static content)

[jacekkarczmarczyk]

I don't see how it's better as well, @edison1105 - as i understand OP is asking about :key="index" vs no key (afaik they're equivalent), not :key="goodKey" vs no key

[edison1105]

Oh~ Sorry. I was careless and misunderstood the question.
They are indeed the same.
Thanks for the @jacekkarczmarczyk clarification of the question.