Skip to the editor
JSGroundwork
JSGroundwork handwritten · web dev
←Back to Prototypes & OOP

Ready to read

JSJavaScript⑂Git◎Interview prepΣDSA in JSSDSystem Design
More topics15›
</>HTML{ }CSS⚛ReactNNext.jsNeNest.jsTSTypeScriptNoNode.js🐳DockerDBSQL & Databases✓Testing🔒Web Security☁Cloud & DevOps◈GraphQL◆Redis☸Kubernetes
☰‹›
Description
All topics›JavaScript›Prototypes & OOP

extends, super, and the chain

advancedlayer I3 · Prototypes & OOP5 tests

Build two classes:

  • Animal — takes a name, and speak() returns "Rex makes a sound"
  • Dog extends Animal — also takes a breed, and its speak() returns the parent's sentence plus " — woof"

Call super() before touching this, and reuse the parent method with super.speak() instead of retyping it.

Stuck?

All exercisesPlayground
1234567891011121314
loading the editor…

Nothing yet — hit Run and whatever you log shows up here.

Submit to see how you did.

⌘/Ctrl + Enter run⌘/Ctrl + S save⌘/Ctrl + / comment⌘/Ctrl + F find/replace⌘/Ctrl + D select next matchAlt + click multi-cursorTab indent · ⇧Tab outdentEsc leave fullscreen