Concatenating observables

RxJS enables some operators to combine several observables in a single one containing the events from all, the most common operators are concat() and merge(), which simply creates a new observable containing all data from the others, but in this chapter we will also learn how to do more interesting combinations with other operators.

Using the concat() operator

The most common operator to concatenate two sources of data (observables) is the concat() operator. This operator receives multiple observables as arguments and concatenates all observables from the left to right. It preserves the order of the elements in the observables and only propagates data from the next observable if the current one is already terminated.

This operator has the...