Some things are so basic and fundamental to web development that it can be surprising when someone is not all together clued up with them.
I do find myself often avoiding such areas, a prime example is Fetch() or basic HTTPS calls, really almost any kind of network, disc or database operation.
So it is not surprising that I do have a bit of a library dependence on things. Sure they simplify life but they also abstract the underlying operations.
Instead of having to then write
SELECT * FROM deadbeat_dads WHERE child="me"
in Laravel I can just write, and assuming only 1 child per Dad :P
DeadBeatDads::where('child','me')->get()
In Javascript land, there is a library for everything, even for things built into the language. Then you get node.js which is just a backend that runs on JS.
Why many like it is because now you have one language for both front and back, which I don't really think is completely the right way to think about it. You still have two different contexts and when working with SSR for example, that will bite you in the ass more often than not.
Needless to say, the context switch for me in Node and the different frontend frameworks like Nuxt can be super irritating.
Anyway now I am rambling.
Getting back on topic. One of the many things I avoid, or at least it feels like it. Is Fetch().
A while back it took me more time than I care to admit to do a simple Fetch() call from JS to one of the Hive RPCnodes ... Turns out you need to be posting data.
I finally figured out the required Json to be sending by looking at network calls made by Peakd, and I think Beeswap and proceeded to fail like a dumbass because I did not set it to be a POST.
Aside from that and some tips from 
The moment I want to build a botty whose only job is to get info and respond to said info, what do I do?
I reach for a library.
Now after some trial and error, I even read some docs. I am pretty sure I can say that 
In my opinion a Hive library pretty much needs 4 things.
Everything else can pretty much just be helpers. Want to get a block range but be given all the comments only? Sure put that into the library.
It seems more approachable and it does have all the frontend functionality you might want. It is promise based, has these docs which are actually very helpful https://openhive-network.github.io/dhive/ and most chatter in discord when I do searches use Dhive as an example. Hive docs use it for their snippets.
And most naively it has a getBlocks() method :P
Remember the cover image? Yes the Hive Api call for fetching a bunch of blocks in one go is block_api.get_block_range and it is as simple as it gets, give it a start and a range. It will then return those blocks for you.
In my mind I am like that is nice, so proceeded to use the getBlocks() method in Dhive, very confident that this is the same thing, it even has smartness baked in where it knows when I am at the head and will just keep fetching as new blocks come in.
Obviously I am not the smartest cookie.
The getBlocks method worked just fine, until I decided to get blocks from way way back to the current height. At first I figured oh it is probably fine, like it will speed up, sure 1-2 seconds a block is ok, it makes sense, oh look in production it is 0.5seconds - 2seconds, oh wow local is slow; yeah; ok that was 4 minutes for 100 blocks; that is in production; OK... WTF!!!!
Needless to say it never hit me what getBlocks is actually doing, and it should have since I know already that "streaming" on Hive means hit the endpoints BLAZINGLY fast until you get something new.
To be fair, I really don't know if get_block_range is new in the Hive API and unfortunately it has no usage policy aside from me asking say 
As mentioned local vs production and probably some other things affect the speed at which I get these blocks, but using the get_block_range call directly via Dhive's client.call() method will be in the range of 10x faster.
If only because you are not doing 100 handshakes.
Fetching 100 blocks in this Repl I think shows the diff well enough and really network differences only increase the baselines.
Using getBlocks() to run a replay is pretty much the stupidest thing I could have done.
So for my usecase it will be a case of just having a toggle, if the code recognizes it is behind by say 100 or more blocks it should switch over to the get_block_range call and if it is pretty much in sync with the chain then go ahead and use the getBlocks method.
I would do that because getBlocks already handles a few things, such as also providing errors...
Get_block_range only returns an empty array if you are out of bounds, but then again if I need to be getting the headblock number anyway I can just always flatten the range and use get_block_range all the time or wait until I am 100 blocks behind.
I guess each to their own, but thinking of it now building a change over sounds like a problem also considering the flow of the code. Although depending what you are doing there might be a need for realtime data once caught up then changing from bulk to streaming is probably a good idea.
Anyhow, here is the code from the Repl above. It is as simple as can be expected from my ass, and probably still wrong but as stated in the title. Note to self.
import { Client } from "@hiveio/dhive";
const client = new Client(["https://api.hive.blog",
"https://api.deathwing.me","https://api.hivekings.com",
"https://anyx.io", "https://api.openhive.network"]);
const startBlock = 68990869
const range = 100
const getBlocksRange = range - 1
let blocks = []
//direct call
console.log('block range start time',new Date())
const getBlocks = await client.call('block_api','get_block_range',
{"starting_block_num": startBlock,
"count": range
})
// console.log(getBlocks)
console.log('block range total',getBlocks.blocks.length)
console.log('block range end time',new Date())
console.log('====================')
console.log('getBlocks start', new Date())
for await (const block of client.blockchain.getBlocks(
{ from: startBlock, to: startBlock + getBlocksRange })) {
blocks.push(block)
}
console.log('getBlocks end', new Date())
console.log(blocks.length)