bufferutil is what makes ws fast. It provides some utilities to efficiently perform some operations such as masking and unmasking the data payload of WebSocket frames.

npm install bufferutil --save-optional 

The --save-optional flag tells npm to save the package in your package.json under the optionalDependencies key.

The module exports two functions.

Masks a buffer using the given masking-key as specified by the WebSocket protocol.

• source - The buffer to mask.
• mask - A buffer representing the masking-key.
• output - The buffer where to store the result.
• offset - The offset at which to start writing.
• length - The number of bytes to mask.

'use strict';constbufferUtil=require('bufferutil');constcrypto=require('crypto');constsource=crypto.randomBytes(10);constmask=crypto.randomBytes(4);bufferUtil.mask(source,mask,source,0,source.length);

Unmasks a buffer using the given masking-key as specified by the WebSocket protocol.

• buffer - The buffer to unmask.
• mask - A buffer representing the masking-key.

'use strict';constbufferUtil=require('bufferutil');constcrypto=require('crypto');constbuffer=crypto.randomBytes(10);constmask=crypto.randomBytes(4);bufferUtil.unmask(buffer,mask);

MIT