JS Built-ins
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FinalizationRegistrybeginner

FinalizationRegistry — instanceof

📖 Usage Example
const registry = new FinalizationRegistry(key => {
  console.log(key, 'was GC-ed')
})

FinalizationRegistry calls a cleanup callback when a registered object is garbage collected.

FinalizationRegistry Constructor

new FinalizationRegistry(() => {}) instanceof FinalizationRegistry is true.

Challenge: Verify the instanceof check.

💡 Hints (1)
  • • FinalizationRegistry accepts a callback function called when registered objects are GC'd.