Another similar gotcha is that the global-scoped `name` variable must be a string. See https://developer.mozilla.org/en-US/docs/Web/API/Window/name for details. var name = true; typeof name; // "string", not "boolean" Luckily, this is not true within ES modules which you probably use most of the time anymway.
That's not magic, it's just how property getter and setters work on the global:
var _value = "test value";
Object.defineProperty(window, "testName", {
get: () => _value,
set: (value) => { _value = String(value) },
});
var testName = {};
// prints [object Object] string
console.log(testName, typeof testName);
var name = {};
// prints [object Object] string
console.log(name, typeof name);
Other properties have the same behavior, for example `status`.
Note: there's also LegacyUnforgeable which has similar behavior: https://webidl.spec.whatwg.org/#LegacyUnforgeable
Even if you're not using modules, using an IIFE avoids all this by making your variables local instead of having them define/update properties on the global.