avoid redundant computations

Identify and eliminate computations that are performed repeatedly when they could be executed once. This includes moving loop-invariant checks outside of loops and reducing callback overhead that creates unnecessary function declarations.

Common patterns to optimize:

• Loop invariants: Move conditions that don’t depend on individual loop items outside the loop
• Repeated function calls: Cache results of expensive operations that don’t change
• Callback overhead: Minimize complex function declarations that cause GC churn

Example from file upload validation:

// Before: checking upload limit for every file
filesArray.some(file => {
  // ... file-specific checks ...
  || (files.length + media.size + pending > maxMediaAttachments)  // This doesn't depend on individual file!
})

// After: check upload limit once before processing files
if (files.length + media.size + pending > maxMediaAttachments) {
  // handle error
  return;
}
// Then process individual files without redundant check

This optimization reduces computational overhead and improves performance, especially in scenarios with loops, callbacks, or frequently called functions.