EMMA TWERSKY: Hi. I'm Emma, a senior
developer relations engineer on the Angular team. Today, I'm here to share some
fantastic news about Angular and the future of
change detection. Change detection is how Angular
updates the UI in the browser when the state in
the app changes. This could be from
user interaction, or maybe some new
data is available. Making something happen
when there's a change is called reactivity. Angular's reactivity today
runs change detection all over your whole application. But what if we were to
rethink reactivity in Angular? Well, that's exactly
what we've been doing. Before we move on, let's
discuss reactivity. So what is reactivity? What if Angular knew more about
which state in your application was changing and
when it changed? Even better, what if your
state could tell Angular itself where it's used
and when it changes so Angular could
automatically update whatever depends on that value? With this level of
fine-grained control, we believe that
application developers can build scalable,
performant applications while taking advantage of
the features and tooling they love from Angular. With these goals in
mind, we found a solution that we think developers
and their teams will love. Introducing Angular signals. You might have come
across information about our plans to update
Angular to use signals. So we have another
surprise for you. Angular signals are in developer
preview in version 16 today. We cannot wait for
you to try them out. To help you get
started, let's cover a few of the foundational
concepts together. Signals have three
core concepts that we call reactive primitives--
signal, computed, and effect. A signal is like a variable and
holds a value that can change. Unlike variables,
signals can notify Angular when they change. A computed is a kind of signal
that calculates its value from other signals
and only updates if the values it
depends on change. Then we have effects. Effects are functions
that execute when the values of the
signals they use change, giving developers
the opportunity to respond to those changes
in a meaningful way. All right. Now that we have the
fundamental concepts covered, the next step is for you to get
started and try it yourselves. Once you do, we want
to know what you think. You can get started by heading
to goo.gle/angular-signals. All right. That's it for me. And for you, that's your
signal to NG update. Bye. [MUSIC PLAYING]
