Errors should not be created without being thrown

Why you should care

Creating a new Error without actually throwing it is useless and is probably due to a mistake.

How we detect

CAST Highlight counts one occurrence each time ‘throw‘ is not used before the ‘new‘ operator used to instanciate an error class (Error | EvalError | InternalError | RangeError | ReferenceError | SyntaxError | TypeError | URIError).

Bad Code 

if (x < 0) {
  new Error("x must be nonnegative");

Good Code 

if (x < 0) {
  throw new Error("x must be nonnegative");



About CAST and Highlight’s Code Insights

Over the last 25 years, CAST has leveraged unique knowledge on software quality measurement by analyzing thousands of applications and billions of lines of code. Based on this experience and community standards on programming best practices, Highlight implements hundreds of code insights across 15+ technologies to calculate health factors of a software.