JavaScript

private closure in JavaScript

JavaScriptClosuresprivate stateintermediate

What this snippet does

Factory functions with closures provide true privacy — unlike class properties, the private variables are physically inaccessible.

Expected output

Alice logged in (1x)
Alice logged in (2x)
Alice
undefined

Why practise typing this

Typing closures code builds muscle memory for the symbols and indentation JavaScript uses most, which prose-based typing tests never cover. DevType measures your words per minute and accuracy on this snippet and tracks the individual characters you mistype, so later lessons can target them.

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