1 input stream,
projectfunction and the resulting value is emitted
returns a new stream of projected values
❚ map and all the other reactive programming functions will never modify the input stream. Instead, they return a new stream. This principle is called immutability.
In the video example,
▬ isChecked is used as a project function. This function accepts events from checkable elements: checkboxes, radio buttons, options of a menu, toggles, etc. It returns
✔ true if the element is checked,
✘ false otherwise.
When an action is performed on the toggle (on→off or off→on), a toggle event is emitted (read a stream of toggle events).