isWeakSet()

isWeakSet(value): value is WeakSet<any>

Checks if value is a WeakSet.

DEPRECATED

Use instanceof WeakSet directly instead.

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Parameters

value: unknown

The value to check.

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Returns: value is WeakSet<any>

true if value is a WeakSet, else false.

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See Also

WeakSet - MDN

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Since

2.0.0

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Also known as

isWeakSet (Lodash, es-toolkit) · ❌ (Remeda, Radashi, Ramda, Effect, Modern Dash, Antfu)

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Example

// ❌ Deprecated approach
isWeakSet(new WeakSet());  // => true
isWeakSet(new Set());      // => false

// ✅ Recommended approach
new WeakSet() instanceof WeakSet;  // => true
new Set() instanceof WeakSet;      // => false

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How it works?

Checks if value is a WeakSet. Deprecated: Use instanceof WeakSet directly.

Native Equivalent

// ❌ isWeakSet(value)
// ✅ value instanceof WeakSet

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Use Cases

Check WeakSet 📌

Check if value is a WeakSet.

#weakset#set#check#instanceof

new WeakSet() instanceof WeakSet;  // true
new Set() instanceof WeakSet;      // false

Type detection

Identify collection type for serialization.

#type#detection#collection

function getCollectionType(value: unknown) {
  if (value instanceof WeakSet) return 'WeakSet';
  if (value instanceof Set) return 'Set';
  if (Array.isArray(value)) return 'Array';
  return 'unknown';
}