LowFile-scopeJavaScript / TypeScript Plug & play

Always use strict equality checks

Ensure that strict equality (===) is used instead of loose equality (==). Loose equality can lead to unexpected type coercion and logical errors.

Why this matters

Loose equality (==) can cause unexpected behavior due to type coercion. Always use strict equality (===) to prevent logical errors.

Side-by-side examples engineers can pattern-match during review.

Avoid

if (userInput == 0) {
  console.log('This might cause type coercion vulnerabilities');
}

Prefer

if (userInput === 0) {
  console.log('This avoids type coercion issues');
}

Bad

if (userInput == 0) {
  console.log('This might cause type coercion vulnerabilities');
}

Good

if (userInput === 0) {
  console.log('This avoids type coercion issues');
}

From the same buckets as this rule.

Critical
Avoid equality operators in loop termination conditions
Check if loops use equality operators (== or !=) in termination conditions. These can lead to infinite loops if the condition is never met exactly. Instead, use relational operators like < or > for safer loop termination.
error-handlingreadability-refactor
Critical
Avoid Returning Null in Non-Async Task Methods
Returning null from a Task or Task<T> method causes a NullReferenceException if awaited. Use Task.CompletedTask or Task.FromResult<T>(null) instead.
error-handlingreadability-refactor+1
Critical
Avoid Using Boolean Expressions in `except` Statements
Detect `except` clauses that use `or` or `and` to catch multiple exceptions. This does not work as intended. Recommend using a tuple of exceptions instead.
error-handlingstack-python