Counterexample to Dan's tweet https://twitter.com/dan_abramov/status/1081595453660106752

yolo.js

/**
 *
 *  A very simple refactoring that eliminates the need for a comment "This is the first attempt".
 *
 *  I am not going to go into the details of why code is better than comments, books like
 *  The Pragmatic Programmer and Fowler's Refactoring provide well-reasoned arguments as to why
 *  this is the case.
 *
 */

// Original
function updateSuspenseComponent(
  current,
  workInProgress,
  renderExpirationTime,
) {
  const mode = workInProgress.mode;
  const nextProps = workInProgress.pendingProps;

  // We should attempt to render the primary children unless this boundary
  // already suspended during this render (`alreadyCaptured` is true).
  let nextState: SuspenseState | null = workInProgress.memoizedState;

  let nextDidTimeout;
  if ((workInProgress.effectTag & DidCapture) === NoEffect) {
    // This is the first attempt.
    nextState = null;
    nextDidTimeout = false;
  } else {
    // Something in this boundary's subtree already suspended. Switch to
    // rendering the fallback children.
    nextState = {
      timedOutAt: nextState !== null ? nextState.timedOutAt : NoWork,
    };
    nextDidTimeout = true;
    workInProgress.effectTag &= ~DidCapture;
  }
}

// Refactor

function updateSuspenseComponent(
  current,
  workInProgress,
  renderExpirationTime,
) {
    
  function firstAttempt(workInProgress) {
    return (workInProgress.effectTag & DidCapture) === NoEffect
  }
    
  const mode = workInProgress.mode;
  const nextProps = workInProgress.pendingProps;

  // We should attempt to render the primary children unless this boundary
  // already suspended during this render (`alreadyCaptured` is true).
  let nextState: SuspenseState | null = workInProgress.memoizedState;

  let nextDidTimeout;
  if (firstAttempt(workInProgress)) {
    nextState = null;
    nextDidTimeout = false;
  } else {
    // Something in this boundary's subtree already suspended. Switch to
    // rendering the fallback children.
    nextState = {
      timedOutAt: nextState !== null ? nextState.timedOutAt : NoWork,
    };
    nextDidTimeout = true;
    workInProgress.effectTag &= ~DidCapture;
  }
}

In this case, I'd probably use a temp var rather than a func or comment:

const isFirstAttempt = (workInProgress.effectTag & DidCapture) === NoEffect

I tend to use temp vars instead of comments or functions for one liners.