Hi I am trying to use spec library in my re-frame project. When I try to run the code in repl it doesn work and I get this error CompilerException java.lang.ClassNotFoundException: cljs.spec.alpha, compiling:. and CompilerException java.lang.RuntimeException: No such var: s/valid?

Here is the source:

(ns app.db
  (:require [cljs.spec.alpha :as s :include-macros true]))

;; Modeling Application state
(s/def ::name string?)
(s/valid? ::name "John Doe")

hey everyone. I have a bit trouble with with class.eval function. I have following wrapper for evaluating strings in clojurescript in nodejs

(defn eval-str [s]
      (eval
        (empty-state)
        (read-string s)
        {:eval       js-eval
        ;  :load (fn [_ cb] (cb {:lang :clj :source "(ns foo.core) (defn add [a b] (+ a b))"}))
         :source-map false
         :verbose    true
         :context    :expr
        ;  :ns 'foo.core
         :load-macros true}
        (fn [result] 
          (println "result>>" result)
          result
        )))

(eval-str "(do (require '[cuerdas.core :as cue])(cue/slug \"Hello\"))")

@podviaznikov require is a top-level thing in ClojureScript (it can’t be properly processed inside a do)

There is a cljs.js/eval-str function that might be more straightforward to use

The biggest challenge will be in defining the load-fn; I'd recommend perhaps taking a look at the Lumo codebase for an example of how this can be done with Node

Is it safe nowadays to access a nested javacript property like this (.. e -target -value)? Will it be properly handled by advanced compilation?

@viebel there’s a compiler option :infer-externs that works in many cases. However it’s not bullet proof but you can add (set! *warn-on-infer* true) on top of the file you’re working with to see if it’s working or if you need to provide extra hints for the compiler to generate needed externs.

Check out https://clojurescript.org/guides/externs#externs-inference

If you want to play safe you can use libs from cljsjs where someone else has already created the externs file for you.

What about code that relies on native javascript properties like (.. e -target -value) in a event handler?

@viebel I think the best bet is to use getValueByKeys from https://google.github.io/closure-library/api/goog.object.html or https://github.com/appliedsciencestudio/js-interop/

or https://github.com/binaryage/cljs-oops

Yeah. Currently, I am using purnam but it is not maintained any more. So I’ll probably migrate to https://github.com/appliedsciencestudio/js-interop/ @rakyi

AFAIK there’s no problem with any of the cljs oob interop patterns with :advanced unless you’re accessing objects/functions in :foreign-libs.

So I’d say that using a lib to access object properties is unnecessary, unless you’re working with :foreign-libs.