Processing graph-data. Each of node has a type. I leverage this knowledge to not 'ask', but tell what I want to do.

emptyFnLeverageExample.js

function emptyFn() {}

function matchNode(node, typeFunctions) {
  return (typeFunctions[node.type] || emptyFn)(node);
}

// Example usage:

neighbourList.forEach(function(node) {    
  result = result.concat(
    matchNode(node, {
      Type1: continuationForType1,
      Type2: continuationForType2...
    })
  )
});