What this snippet does
Command pattern encapsulates each action as an object with execute and undo — making history and undo trivially composable.
Expected output
Hello World Hello
Why practise typing this
Typing design patterns 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.
More JavaScript practice
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