Arithmetic operators should only have numbers as operands

Expressions with arithmetic (/, *, %, ++, --, -, -=, *=, /=, %=, +=, +), unary (-), or comparison operators (>, <, >=, <=) where one, or both, of the operands is a String, Boolean or Date value rely on implicit conversions. Both the maintainability and reliability levels of such a piece of code are questionable.

Noncompliant Code Example

str = "80";
quarter = str / 4; // Noncompliant

if (str < 10) { // Noncompliant
   // ...
}

Compliant Solution

str = "80";
parsedStr = parseInt(str);
quarter = parsedStr / 4;

if (parsedStr < 10) {
  // ...
}

Exceptions

• Expressions using the binary + operator with at least one String operand are ignored because the + operator will perform a concatenation in that case.
• Comparisons where both operands are strings are ignored because a lexicographical comparison is performed in that case.