Calculate the CSP hash of a script in the browser console

csp-hash.js

const scripts = document.getElementsByTagName("script"),
  script_content = scripts[scripts.length - 1].innerHTML,
  enc = new TextEncoder(),
  data = enc.encode(script_content);

crypto.subtle.digest('SHA-256', data).then(function(val) {
  const digest = ["sha256", _arrayBufferToBase64(val)].join("-");
  console.log(`The digest for your script is: ${digest}`);
});

function _arrayBufferToBase64(buffer) {
  var binary = "";
  var bytes = new Uint8Array(buffer);
  var len = bytes.byteLength;
  for (var i = 0; i < len; i++) {
    binary += String.fromCharCode(bytes[i]);
  }
  return window.btoa(binary);
}