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Closuresadvanced

Closures — Closure preserves reference (advanced)

📖 Usage Example
const obj = { count: 0 }
const inc = () => ++obj.count
inc()       // → 1
obj.count = 10
inc()       // → 11

Closures capture object references rather than copies, so any mutation to the object is immediately reflected when the closure is later invoked.

Mutable Object References in Closures

A closure captures a reference to an object, so mutations to that object are visible through the closure.

Challenge: Create an object, then create a closure that references it. Modify the object after creating the closure and verify that the closure sees the updated values.

Example:

const obj = { count: 0 }
const incrementCount = () => ++obj.count
incrementCount()    // 1
obj.count = 10
incrementCount()    // 11
💡 Hints (3)
  • • Closures capture references, not copies
  • • Objects are mutable, so changes after closure creation are visible
  • • This is different from primitive values which are immutable