Can't access Imported Node Module from within Node stdin

Question

Why can't I access this?

someFile.js

const Context = require('./Context');

    const play = function(){
      process.openStdin().on('data', function(res) {
         if(Context.move(res, X)){ // I get an error here saying Context is undefined
            ... rest of the code
          }
   }

I'd like to not have to modify the behavior, the code in play as much as possible.

Answer 1

If you're in any kind of modern Node, preserve your context with an arrow function:

const Context = require('./Context');

const play = () => {
  process.openStdin().on('data', res => {
     if(Context.move(res, X)){
        ... rest of the code
     }
  });
};