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Most information on it seems to start off as a T.V. infomercial for some library. Don't suffer from callback hell, use X!
I can barely find anything on the internet about callback hell before 2010 to indicated that it was a real problem at all with javascript.
Even then, I think it's a bit overstated - people were writing event-driven servers in C++ before Javascript was even invented. I do think that being able to use semicolons to sequence two statements is a lot more concise than nesting a chain of closures, though.
It depends on how much of your business logic must be synchronous and how much it relies on asynchronous operations. It also depends on what you consider to be hellish.
async/await is still cleaner than even a single promise, so you might as well use it.
Let's use NodeJS with Express and with pg-node. Let's say you have a database.
1. You define an Express handler to handle a get request.
2. In that handler, you connect to a database, which takes a callback
3. You create a query on that connection, this takes a callback.
4. You then write a function that feeds the query result rows into a CSV exporter, which takes a callback (because of course it does).
However, I've found that pipeline of promises almost completely solve that problem.
So, I think an example here will help you understand. Let's use NodeJS with Express and with pg-node. Let's say you have a database. 1. You define an Express handler to handle a get request. 2. In that handler, you connect to a database, which takes a callback 3. You create a query on that connection, this takes a callback. 4. You then write a function that feeds the query result rows into a CSV exporter, which takes…
So, I think an example here will help you understand. Let's use NodeJS with Express and with pg-node. Let's say you have a database. 1. You define an Express handler to handle a get request. 2. In that handler, you connect to a database, which takes a callback 3. You create a query on that connection, this takes a callback. 4. You then write a function that feeds the query result rows into a CSV exporter, which takes…
I mean if I didn't have the option of using promises, I would have probably written something like this.
function handler(callback){
var state={};
function logic(step,err,data){
if(!step){
connectToDb("somedatabase",logic.bind(state,1))
}
if(step==1){
if(err) callback("error1")
state.dbInstance=data
state.dbInstance.query("someQuery",logic.bind(state,2))
}
if(step==2){
if(err) callback("error2")
csvExporter(data,logic.bind(state,3))
}
if(step==3){
if(err) callback("error3")
callback(data)
}
}
logic()
}