The idea of "buckets" here is purely to speed up search time, at a very low level. Don't think about it in the context of a web server or database storage, its way more base than that. Its literally just arrays in memory.
The idea is: if you don't have a Hash or Map already implemented in your language, how would you build a fast one? You cant write my_object['my_key'], that doesn't exist, you don't have Key-Value storage. You need instead to somehow store those pieces of information, and find them later.
Obviously, you could just stick every value inside one big array. Then when you call MyHash.get('key'), you simply do an array search. But that would be slow.
Instead, you can hash the 'key', stick it into a smaller bucket based on the hash, and then more quickly search for it later. In the future, you know the hash of 'key', so you know which bucket to look in.
The author does make it confusing, since in their example each bucket contains Entry (entry['value']), meaning they are already using a JS HashMap implementation in their rebuilding of a HashMap, but you could rewrite the example to do it without any objects. The code would be harder to read though.
This is my eternal struggle: be correct, or be simple.
I wrote a version that used 2-element arrays but the code became more dense and I worried about losing people. I was hoping that how easy it would be to translate it to not use objects would give me a pass here, but apparently not :D
The idea is: if you don't have a Hash or Map already implemented in your language, how would you build a fast one? You cant write my_object['my_key'], that doesn't exist, you don't have Key-Value storage. You need instead to somehow store those pieces of information, and find them later.
Obviously, you could just stick every value inside one big array. Then when you call MyHash.get('key'), you simply do an array search. But that would be slow.
Instead, you can hash the 'key', stick it into a smaller bucket based on the hash, and then more quickly search for it later. In the future, you know the hash of 'key', so you know which bucket to look in.
The author does make it confusing, since in their example each bucket contains Entry (entry['value']), meaning they are already using a JS HashMap implementation in their rebuilding of a HashMap, but you could rewrite the example to do it without any objects. The code would be harder to read though.