Node.js and Mutexes

Question

I\'m wondering if mutexes/locks are required for data access within Node.js. For example, lets say I\'ve created a simple server. The server provides a couple protocol metho

Answer 1

Mutexes are definitely necessary for a lot of back end implementations. Consider a class where you need to maintain synchronicity of async execution by constructing a promise chain.

let _ = new WeakMap();
class Foobar {
  constructor() {
    _.set(this, { pc : Promise.resolve() } );
  }
  doSomething(x) {
    return new Promise( (resolve,reject) => {
      _.get(this).pc = _.get(this).pc.then( () => {
        y = some value gotten asynchronously
        resolve(y);
      })
    })
  }
}

How can you be sure that a promise is not left dangling via race condition? It's frustrating that node hasn't made mutexes native since javascript is so inherently asynchronous and bringing third party modules into the process space is always a security risk.