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An en dash is defined by its width, not the spacing around it. In fact, spacing around an em dash is permitted in some style guides. On the internet, though, the hyphen has generally taken over from the em dash (an en dash should not be used in that context).
Now, two hyphens—that's a recipe for disaster if I've ever heard one.
Hey, I like double-hyphens as em-dash substitutes!
...but yeah, you're right otherwise.