RxJS: Understanding Lettable Operators
5 min readSep 26, 2017
An update: lettable operators are now officially pipeable operators.
The version 5.5.0 beta of RxJS introduces lettable operators.
Lettable operators offer a new way of composing observable chains and they have advantages for both application developers and library authors. Let’s look briefly at the existing composition mechanisms in RxJS and then look at lettable…