JAVASCRIPT

nodejs create buffer from string

// a string
const str = "Hey. this is a string!";

// convert string to Buffer
const buff = Buffer.from(str, "utf-8");

console.log(buff); // <Buffer 48 65 79 2e ... 72 69 6e 67 21>

node convert buffer to string

// Convert Buffer to String in Node.JS
const someBuffer = Buffer.from("Hey", "utf-8");

someBuffer.toString(); // <= Use the toString() method

buffer to string

Your code is working. The buffer you have is actually the string "[object Object]".

let b = Buffer.from('[object Object]', 'utf8')
console.log(JSON.stringify(b))
// {"type":"Buffer","data":[91,111,98,106,101,99,116,32,79,98,106,101,99,116,93]}

console.log(b.toString('utf8'))
// [Object object]
The problem you need to figure out is why is a buffer with that string being sent. It seems like the sender of the buffer needs to call stringify or otherwise serialize the object before sending it. Then you can turn it back to a string with toString() and use JSON.parse() on the string.