rxjs 合并 http 响应

Question

Multiple http requests are concurrent, and the number of concurrent requests can be controlled. After all the requests are completed, data can be merged (data can be ordered or unordered)

from([link, link, link]).pipe(
   merge(l => request.get(l)),
   // something...
)

return [linkdata, linkdata, linkdata]

Answer 1

Consider implementing it as demonstrated below:

from([link1, link2, link3]).pipe(
  mergeMap(request.get, CONCURRENT_NUMBER), // <= limit the number of active inner subscriptions at a time
  toArray() // <= transform stream into array prior to completion 
)
.subscribe(([result1, result2, result3]) => { })

Answer 2

Seem like you need to use forkJoin

const links = [link1, link2, link3]; // assump `links` is an array of string

forkJoin(
  from(links).pipe(
    mergeMap((link: string) => {
      return http.get(link); // returns an observable
    }),
    toArray()
  )
).pipe(
   map(array => array[0]) // data stream is in [[data]] format, you only need head
); // [link1data, link2data, link3data]

Answer 3

I think you are searching for mergeAll

from([link1, link2, link3].map(link => request.get(link))).pipe(
  mergeAll(CONCURRENT_NUMBER),
  // something like reduce, toArray... to combine the results
).subscribe(console.log);