您可以使用WebCrypto API来计算SHA-256哈希。

window.crypto.subtle.digest(
  {
    name: "SHA-256",
  },
  imageFileData // The image file data you want to calculate a hash for as an ArrayBuffer
)
.then(function(hash) {
  // convert the hash to byte array
  const hashArray = Array.from(new Uint8Array(hash));                     
  // convert bytes to hex string
  const hashHex = hashArray.map(b => b.toString(16).padStart(2, '0')).join(''); 
  // use the hashHex string for comparison
})
.catch(function(err) {
  console.error(err);
});

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