Demo: merge
The merge subscribes the given list of observables in parallel and adds their output into a single output stream.
const input_1 = timer(500,1000).pipe(take(3));
const input_2 = interval(2000).pipe(take(2));
//Runs the observables in parallel and
//adds their outcome into a single output stream
const mergedOutput = merge(input_1 , input_2);
const output = mergedOutput.subscribe(v=>console.log(v))More on :
merge
As seen above, the merge enables us to run a set of observables(or tasks) in parallel.
Since, the observables run in parallel, the final output does not follow the same order as the input but, depends on the response times of the provided observables.