closure-over-multiple-parameters

before.js

// Before
function recordMetricOnCompletion(metricName, promise) {
  const metric = Metric.newTimedMetric(metricName);
  
  return promise
    .then(values => {
      metric.emitSuccess();
      return Promise.resolve(values);
    })
    .catch(reason => {
      metric.emitFailure();
      return Promise.reject(reason);
    });
}

refactor.js

// After
function getRecordedPromise(metricName) {
 const metric = Metric.newTimedMetric(metricName);
  
 return (promise) => {
  return promise
    .then(values => {
      metric.emitSuccess();
      return Promise.resolve(values);
    })
   .catch(reason => {
      metric.emitFailure();
      return Promise.reject(reason);
    });
 }
}