Clojurians Log v2

The reagent docs have this code example:

(defn lister [items]
  [:ul
   (for [item items]
     ^{:key item} [:li "Item " item])])

It seems like this is Reagent metadata?

It’s syntax for adding metadata to the vector being constructed

Reagent checks a few places for keys when converting a vector into a React element

One is props , so you could just pass in the key like any other prop

Another is metadata on the vector

to be clear, ^{:foo bar} is vanilla clojure, and puts a metadata map onto a collection or symbol, but reagent has a special interpretation of specific metadata keys

^:foo is often seen, it translates to ^{:foo true}

you can combine them

ins)cljs.user=> (def m ^:foo ^{:bar false} {})
#'cljs.user/m
(ins)cljs.user=> m
{}
(ins)cljs.user=> (meta m)
{:bar false, :foo true}

yeah I feel some of the docs are just outdated, thing is, when learning, it is hard to determine which thing is wrong