[naasking]

JS signals come from functional reactive programming, which is a generalization of synchronous reactive programming from the Lustre and Esterel programming languages from the 80s and 90s. I believe the first version was FrTime published in 2004.

You can think of reactive signals as combining an underlying event system with value construction, ultimately defining an object graph that updates itself whenever any of the parameters used to construct it change. You can think of this graph like an electronic circuit with multiple inputs and outputs, and like a circuit, the outputs update whenever inputs change.