How to decode base64 encoded json object string in Node JS?

To decode a base64 encoded JSON object string in Node.js, you can use the Buffer module’s Buffer.from method to convert the base64 encoded string to a buffer, and then use the JSON.parse method to parse the buffer into a JavaScript object.

Here’s an example:

const base64EncodedJsonString = 'eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ==';

// Convert the base64 encoded string to a buffer
const buffer = Buffer.from(base64EncodedJsonString, 'base64');

// Parse the buffer into a JavaScript object
const jsonObject = JSON.parse(buffer);

console.log(jsonObject); // { sub: '1234567890', name: 'John Doe', iat: 1516239022 }

Note that the Buffer.from method is available in Node.js 6.0.0 and later. If you’re using an older version of Node.js, you can use the new Buffer constructor instead:

const buffer = new Buffer(base64EncodedJsonString, 'base64');