es module observable error "could not be converted"

hi!

i’m trying to set up a modern build-free app using mobx, htm, preact, and native es modules

i get an error when i try to use observable

esmodule (codepen)

• import {observable} from "https://unpkg.com/mobx@5.9.0/lib/mobx.es6.js"
  observable("anything")
  

error

• Uncaught Error: [mobx] The provided value could not be converted into an
  observable. If you want just create an observable reference to the object 
  use 'observable.box(value)'
  
    invariant$$1 @ mobx.es6.js:16
    fail$$1 @ mobx.es6.js:11
    createObservable @ mobx.es6.js:402
    (anonymous) @ pen.js:4
  

i don’t know what’s wrong

---

I have a:

• Issue:
  • Provide error messages including stacktrace

    • Uncaught Error: [mobx] The provided value could not be converted into an
      observable. If you want just create an observable reference to the object 
      use 'observable.box(value)'
      
        invariant$$1 @ mobx.es6.js:16
        fail$$1 @ mobx.es6.js:11
        createObservable @ mobx.es6.js:402
        (anonymous) @ pen.js:4
      

  • Provide a minimal sample reproduction. Create a reproduction based on this sandbox
    • its only two lines but i have this codepen
  • Did you check this issue wasn’t filed before?
  • Elaborate on your issue. What behavior did you expect?
    • i expected observable not to throw an error for primitives like strings or numbers
  • State the versions of MobX and relevant libraries. Which browser / node / … version
    • mobx@5.9.0, chrome@71.0

[fi3ework]

@chase-moskal The target of observable should be an object. If you wanna observe a primitive value, please use observable.box, see details here.

[Maaartinus]

@chase-moskal I’m a beginner here, but isn’t this what the documentation says?

The string "anything" is immutable and therefore

• it can’t be made observable
• there’s nothing to observe as it can’t change

A primitive-valued field is a different story.