how to do chained axios requests in multiple loop?

Question

Here is the condition: there are three requests:
the Axios_Request_1 returns an array => Array_1
now the Axios_Request_2 go through the Array_1,with all response data get Array_2
the last request Axios_Request_3 go through Array_2. and generate the desired Array_3 I konw with promise.all it could be done like this

let Array_1 = await Axios_Request_1

let Promise_1 = []
for (const ca of Arrya_1) {
   Promise_1.push(Axios_Request_2(ca))
}

let Array_2 = await Promise.all(Promise_1)

let Promise_2 = []
for (const product of Array_2) {
    Promise_2.push(Axios_Request_3(product ))
}

let Array_3 = await Promise.all(Promise_2)

But it's slower than what I wanted like this:

let Array_3 = []
Axios_Request_1.then(function(Array_1){
    for (const ca of Array_1) {

        Axios_Request_2(ca).then(Subarray_Array_2=>{

            for (const product of Subarray_Array_2) {

                Axios_Request_3(product).then(element_Array_3=>{

                    Array_3.push(element_Array_3)
                })
        })
})
console.log(Array_3);

It doesnot work as i want. And I tried to put promise.all but doesnot work or I just didnot get it working well,I wonder what can i do to generate result through code like the second one

Answer 1

Chain the Axios_Request_3 call immediately onto the Axios_Request_2 , so that 3 fires as soon as that 2 is done, rather than having to wait for all 2s to finish.

I'd also highly recommend following the standard JavaScript naming conventions - use camelCase for functions and most variables.

const array1 = await axiosRequest1;
const output = await Promise.all(
  array1.map(
    ca => axiosRequest2(ca)
            .then(subarray2 => Promise.all(
              subarray2.map(axiosRequest3)
            ))
  )
);

Might be easier to visualize with a separate named function beforehand.

const getProductsFromSubarray = subarray2 => Promise.all(subarray2.map(axiosRequest3));

const array1 = await axiosRequest1;
const output = await Promise.all(
  array1.map(
    ca => axiosRequest2(ca).then(getProductsFromSubarray)
  )
);

Still, depending on the size of the input array and the size of the responses, there could still be a whole lot of requests to be made in total, so that could be another significant cause of the app feeling slow.