How to decode base64 string to text

FAQs Calculators
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1

If you require to decode a base64 string to text, please follow the instructions below:

Illustrated in the image below is an example of a flow where the payload is from a Record Generator source step which decodes the base64 string into text by using JSON code in a Calculator step.

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The Record Generator source step contains a payload with a Key and base64 encoded value as shown in the below image.

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In the Calculator step, there a function called base64Decode which decodes the base64 string manually using a base64 decoding algorithm and also from the record which contains the base64 string to return the decoded values.

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The output of the Calculator step is shown in the image below.

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Below is the JSON code that is used in the Calculator step:

function base64Decode(base64) {
  const chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
  let decoded = '';

  // Remove any characters that are not A-Z, a-z, 0-9, +, /, or =
  base64 = base64.replace(/[^A-Za-z0-9+/=]/g, '');

  for (let i = 0; i < base64.length;) {
    let c1 = chars.indexOf(base64.charAt(i++));
    let c2 = chars.indexOf(base64.charAt(i++));
    let c3 = chars.indexOf(base64.charAt(i++));
    let c4 = chars.indexOf(base64.charAt(i++));

    let chr1 = (c1 << 2) | (c2 >> 4);
    let chr2 = ((c2 & 15) << 4) | (c3 >> 2);
    let chr3 = ((c3 & 3) << 6) | c4;

    decoded += String.fromCharCode(chr1);

    if (c3 !== 64) {
      decoded += String.fromCharCode(chr2);
    }
    if (c4 !== 64) {
      decoded += String.fromCharCode(chr3);
    }
  }

  return decoded;
}

const obj = input.record;
const decodedValue = base64Decode(obj.FileBase64Value);
obj.FileBase64Value = decodedValue;

return obj;