ClojureScript

Local bindings conflict with global JS namespace

Details

  • Type: Defect Defect
  • Status: Open Open
  • Priority: Minor Minor
  • Resolution: Unresolved
  • Affects Version/s: None
  • Fix Version/s: None
  • Component/s: None
  • Labels:
    None

Description

Not sure if it's a bug or expected behaviour, but this:

(defn test-fn []
  (let [href     js/location.href
        location "123"]
    href))

gets compiled to this (not in advanced mode):

cognician.chat.ui.pages.insights.test_fn = (function cognician$chat$ui$pages$insights$test_fn(){
var href = location.href;
var location = "123";
return href;
});

and local location var shadows global I'm trying to access in location.href.

That sort of thing is expected and one should pay attention and work around stuff like this in JS, but in CLJS it's very confusing because nothing hints what am I doing wrong and why that code fails. I remember one of ClojureScript goals was to fix JS semantics, so maybe there's a way this might be addressed? At least throw a warning, maybe?

Activity

Hide
Thomas Heller added a comment -

This came up recently on the #cljs-dev slack channel. There is definitely a bug somewhere.

(let [href     js/location.href
      location "123"]
  href)

produces

var href_51444 = location.href;
var location_51445 = "123"; // << correct

So it works at the top level, but when inside a defn (and others) we get

(ns test)
(defn test-fn []
  (let [href     js/location.href
        location "123"]
    href))
test.test_fn = (function test$test_fn(){
var href = location.href;
var location = "123"; // << incorrect
return href;
});
Show
Thomas Heller added a comment - This came up recently on the #cljs-dev slack channel. There is definitely a bug somewhere.
(let [href     js/location.href
      location "123"]
  href)
produces
var href_51444 = location.href;
var location_51445 = "123"; // << correct
So it works at the top level, but when inside a defn (and others) we get
(ns test)
(defn test-fn []
  (let [href     js/location.href
        location "123"]
    href))
test.test_fn = (function test$test_fn(){
var href = location.href;
var location = "123"; // << incorrect
return href;
});
Hide
David Nolen added a comment -

Taking a quick look it seems that maybe we aren't checking `:js-globals` consistently and often only looking at locals? Also now that externs inference is a thing we should probably compute `:js-globals` from all known externs instead of the obviously incomplete list we currently have in place.

Show
David Nolen added a comment - Taking a quick look it seems that maybe we aren't checking `:js-globals` consistently and often only looking at locals? Also now that externs inference is a thing we should probably compute `:js-globals` from all known externs instead of the obviously incomplete list we currently have in place.

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Dates

  • Created:
    Updated: