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Structure · easy

9. Classes and Inheritance

Constructors, fields, and extends.

1 min read3 questionsup to 50 XPtopic 9/50

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Classes provide syntactic sugar over prototypes, supporting constructors, private `#fields`, and inheritance with `extends` and `super`.

js
class Wallet {
  #key;
  constructor(address) { this.address = address; }
}

How to study this topic

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  2. 2. Re-read the code snippets and say out loud what each line does.
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Check your understanding

  1. 1. Where do class methods live in memory?

  2. 2. What enforces true private class fields?

  3. 3. What must a derived constructor call before this?

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