I read about the signals in Angular and there are two methods to alter the current value: by set() and update().

Angular has adapted Signals into the framework and have started to build a set of new features that utilize Signals as their cornerstone. Using update allows us to access the current value of the signal , and set allows us to set a new value without caring about the current value.

What puzzles me is that I don’t understand how both are needed (although I see that each can be used). It’s clear that I can. But why?

Let’s say we define an instance like so.

siggy = signal(4);

Then, we can set an absolute value using both of the following ways.

this.siggy.set(1337);
this.siggy.update((a) => 1337);

But we also can use both of those to set a relative one (alter the current).

this.siggy.set(this.siggy() + 1);
this.siggy.update((a) => a + 1);

It seem superfluous to provide multiple ways to reach the same result. Such redundancy is a sign of bad design (or possibly syntactic sugar for DX purposes). I do not in any way suggest that the great folks on Angular team made a poor design! Nor do I see any increase in smoothness. (In fact, even the Angular blog mentions the usage of this.counter.set(this.counter()+1)…)

My conclusion is that there are (edge) cases that I’m ignorant of. What am I missing?