You can think of an ArrayBuffer as a typed Buffer.
An ArrayBuffer therefore always needs a type (the so-called "Array Buffer View"). Typically, the Array Buffer View has a type of Uint8Array or Uint16Array.
There is a good article from Renato Mangini on converting between an ArrayBuffer and a String.
I have summarized the essential parts in a code example (for Node.js). It also shows how to convert between the typed ArrayBuffer and the untyped Buffer.
function stringToArrayBuffer(string) {
const arrayBuffer = new ArrayBuffer(string.length);
const arrayBufferView = new Uint8Array(arrayBuffer);
for (let i = 0; i < string.length; i++) {
arrayBufferView[i] = string.charCodeAt(i);
}
return arrayBuffer;
}
function arrayBufferToString(buffer) {
return String.fromCharCode.apply(null, new Uint8Array(buffer));
}
const helloWorld = stringToArrayBuffer('Hello, World!'); // "ArrayBuffer" (Uint8Array)
const encodedString = new Buffer(helloWorld).toString('base64'); // "string"
const decodedBuffer = Buffer.from(encodedString, 'base64'); // "Buffer"
const decodedArrayBuffer = new Uint8Array(decodedBuffer).buffer; // "ArrayBuffer" (Uint8Array)
console.log(arrayBufferToString(decodedArrayBuffer)); // prints "Hello, World!"