:dump-core

Dump the analysis cache of cljs.core into the output file, allowing you to evaluate basic ClojureScript code at runtime using cljs.js/eval-str without extra setup. Defaults to false.

:dump-core true

When true, adds ~5mb (330kb gzipped) to build size.

Specifically, the cljs.core analysis cache is written inline into the cljs.js/empty-state function, returning a useful default compiler state.

Otherwise, the cljs.core analysis cache would have to be loaded manually via:

(cljs.js/load-analysis-cache! st 'cljs.core cache)

When true, the following code will allow you evaluate basic ClojureScript code at runtime:

(require 'cljs.js)

(cljs.js/eval-str
  (cljs.js/empty-state)
  "(+ 1 2 3 4)"
  {:eval cljs.js/js-eval}
  (fn [res]
    (println res))) ;; <-- prints 10