encodeURIComponentintermediateencodeURIComponent('?key=value') // β '%3Fkey%3Dvalue'
// ? β %3FencodeURIComponent() encodes ? (%3F), making it safe to embed query strings in URLs.
encodeURIComponent('?key=value') encodes ? and =, returning '%3Fkey%3Dvalue'.
Challenge: Verify the encoding.