Replace deprecated Buffer constructor

[varshard]

Buffer constructor has been deprecated because of security reasons and has been replaced with Buffer.from

https://nodesource.com/blog/understanding-the-buffer-deprecation-in-node-js-10/

[iporsut]

Why need check this?

[varshard]

Buffer.from suppose to officially replace new Buffer in v5.x, which suppose to support any parameter that is supported by Buffer(), however the oldest version that we still support (v4.4.6.) also implemented Buffer.from that which would throw this is not a typed array. if key isn't an array.

[phureewat29]

I think this should check the existence method instead of catching and checking the error message when method is not exist in older version of node.

[phureewat29]

By the way, there was a backport of Buffer API to v4.x in v4.5.0. So, the Buffer.from() in versions prior is not the same thing. Please checking the existence of Buffer.allocUnsafe() instead.

// backward compatilibity for 4.x
if (typeof Buffer.allocUnsafe === "function"){
     buffer = Buffer.from(key);
} else {
     buffer = new Buffer(key);
}

[varshard]

@aquartier Checking for existence of Buffer.from isn't enough, because it exist in v4 as well.

allocUnsafe is a good idea. Thanks