Use Suspense Today
Believe it or not, you’ve had access to Suspense
for a year.
Yes, there is more suspense to come.
Yes, that “more” isn’t totally ready.
No, that doesn’t mean you can’t use Suspense
today.
React.lazy and Suspense sitting in a tree
React v16.6
introduced React.lazy
—
A way to code-split in client-rendered applications by components.
lazy
depends on Suspense
to present a fallback while the lazily-loaded component is fetched.
In that way, Suspense
acts as a boundary for asynchronous data.
If a promise inside a Suspense
boundary is pending,
The fallback
is presented.
Once resolved, children
are presented.
But Suspense needs a translator
Suspense
can’t magically know all the promises it’s children
may or may not have.
That’s where lazy
comes in.
It acts as a translator.
lazy
wraps a dynamic import
and communicates Pending
and Resolved
states to the nearest Suspense
component boundary.
(code here).
Suspense
will resolve fallback
or children
accordingly.
The future™️
As we move into a Suspense
future, you’ll see this pattern more often:
A Suspense
boundary (with fallback
)
And data, wrapped in “translator” (React.lazy
, ReactCache.createResource
, etc).
What’s Next? Errors
Not all promises resolve.
Some are Rejected
.
I’ll show you how to handle that state next time.