In JS, expando properties of a function are always treated as static methods

[sandersn]

var assert = function() { };
assert.AssertionError = function (actual, expect) {
    this.name = 'AssertionError';
    this.actual = actual;
    this.expected = expect;
}

Expected behavior:
No errors, and this: AssertionError, and assert.AssertionError is a constructor function.

Actual behavior:
this: typeof assert, which is a function, so that, for example this.name tries to overwrite the built-in Function.name. Basically, assert.AssertionError behaves like a static method of assert instead of a static property that is a constructor function.

Note that usage of assert.AssertionError works as desired: you can say new assert.AssertionError().actual.

[sandersn]

This works correctly if you put @constructor in front of assert.AssertionError. Since the usages are ambiguous, I think this it's OK to require an annotation. You could argue that the annotation be required in the opposite case because it's (possibly) less common, but JSDoc doesn't already have a tag for marking things as static methods, as far as I know.