An asynchronous data stream is a stream of data where values are emitted, one after another, with a delay between them. The word asynchronous means that the data emitted can appear anywhere in time, after one second or even after two minutes, for example. A way to model asynchronous streams is to place the emitted values on a time axis, like so:
There are a lot of things that can be considered asynchronous. One such thing is fetching data through AJAX. When the data arrives depends on a number of factors, such as:
- The speed of your connection
- The responsiveness of the backend API
- The size of the data, and many more factors.
The point is the data isn't arriving right at this very second.
Other things that can be considered asynchronous are user initiated events, such as scrolling or mouse clicks. These are events that can happen at any point in...