Principle: Write code for the reader, not the writer

Code is written once but read many times. Optimizing for writing speed produces code that's expensive to maintain.

Prioritize readability in every decision:

Naming:

• Variables: describe what it IS, not how it's computed

- Bad: filteredSortedItems Good: availableProducts

• Functions: describe what it DOES from caller's perspective

- Bad: processData() Good: calculateMonthlyRevenue()

• Booleans: should read as true/false questions

- Bad: flag, status Good: isVisible, hasPermission

Structure:

• Extract complex conditions into named booleans

  // Hard to read
  if (user.age >= 18 && user.verified && !user.banned && user.credits > 0)
  
  // Easy to read
  const canPurchase = user.age >= 18 && user.verified && !user.banned;
  const hasCredits = user.credits > 0;
  if (canPurchase && hasCredits)
  

• Return early to reduce nesting

  // Hard: deeply nested
  function process(user) {
    if (user) {
      if (user.active) {
        if (user.hasPermission) {
          // actual logic buried here
        }
      }
    }
  }
  
  // Easy: guard clauses
  function process(user) {
    if (!user) return;
    if (!user.active) return;
    if (!user.hasPermission) return;
    // actual logic at top level
  }
  

The test: Can a new team member understand this code in 30 seconds? If not, simplify it.

Code is read 10x more than it's written. The few seconds saved typing a shorter name or skipping a refactor cost minutes every time someone reads it.

All software development