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NewtonCode
NewtonCode

Reputation: 1542

How to implement following using rxjs Observables?

How can I implement the following code using Observables in rxjs?

What I am trying to achieve here is that I have an array of functions, each of which accepts an object, modifies it and returns the object to the next function in the stack.

function A(res:SomeType){
    //Do Something
    return res;
}

function B(res:SomeType){
    //Do Something
    return res;
}

function C(res:SomeType){
    //Do Something
    return res;
}

let fnPipe = [];

fnPipe.push(A); 
fnPipe.push(B);
fnPipe.push(C);

obj= {key:"val"};

fnPipe.forEach((fn)=>{
    obj= fn(obj);
});
console.log(obj);

How can I implement the same using observables in rxjs?

Upvotes: 0

Views: 57

Answers (1)

Federico Galassi
Federico Galassi

Reputation: 682

let fn$ = Observable.from([
  x => x + "a",
  x => x + "b",
  x => x + "c"
])
let value$ = Observable.of("x", "y", "z")

value$
  .concatMap(val => fn$.scan((acc, fun) => fun(acc), val))
  .subscribe(console.log)

/* prints
"xa"
"xab"
"xabc"
"ya"
"yab"
"yabc"
"za"
"zab"
"zabc" */

Upvotes: 1

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