What this snippet does
JavaScript has no abstract keyword — throwing in the base method forces subclasses to override it or crash loudly.
Expected output
Circle(color=red, area=78.54) Rect(color=blue, area=24.00)
Why practise typing this
Typing classes 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
- class syntaxClasses · beginner
- class extendsClasses · intermediate
- static membersClasses · intermediate
- private fieldsClasses · intermediate
- fluent chainingClasses · intermediate
- mixinsClasses · advanced