const text = 'An obscure body in the S-K System, your majesty. The inhabitants refer to it as the planet Earth.';

async function digestMessage(message) {
  const encoder = new TextEncoder();
  const data = encoder.encode(message);
  const hash = await crypto.subtle.digest('SHA-256', data);
  return hash;
}

digestMessage(text)
  .then((digestBuffer) => console.log(digestBuffer.byteLength));

将摘要转换为十六进制字符串

摘要以 ArrayBuffer 的形式返回，但为了进行比较和显示，通常会使用十六进制（hex）字符串的形式表示。此示例计算摘要，然后将 ArrayBuffer 转换为十六进制字符串：

const text = 'An obscure body in the S-K System, your majesty. The inhabitants refer to it as the planet Earth.';

async function digestMessage(message) {
  const msgUint8 = new TextEncoder().encode(message);                           // 编码为（utf-8）Uint8Array
  const hashBuffer = await crypto.subtle.digest('SHA-256', msgUint8);           // 计算消息的哈希值
  const hashArray = Array.from(new Uint8Array(hashBuffer));                     // 将缓冲区转换为字节数组
  const hashHex = hashArray.map((b) => b.toString(16).padStart(2, '0')).join(''); // 将字节数组转换为十六进制字符串
  return hashHex;
}

digestMessage(text)
  .then((digestHex) => console.log(digestHex));

规范

Specification
Web Cryptography API # SubtleCrypto-method-digest

浏览器兼容性

BCD tables only load in the browser

备注： Chrome 60 添加了对非 TLS 连接禁用 crypto.subtle 的特性。