FormDataadvanced

FormData — entries() iterator has Symbol.iterator

📖 Usage Example

const fd = new FormData()
fd.append('x', '1')
fd.append('x', '2')
[...fd].length  // → 2 (counts each entry)

Spreading FormData gives all [key, value] entries including duplicate keys.

FormData entries iterator protocol

The iterator returned by entries() implements the iterable protocol, meaning it has a Symbol.iterator method.

Challenge: Verify that typeof fd.entries()[Symbol.iterator] is 'function'.

💡 Hints (1)

• Iterators that also implement Symbol.iterator are called iterables — they can be used in for...of loops

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