simplify-boolean-expression.md

Forbid defining function inside boolean expressions (simplify-boolean-expression)

Function expressions can be very useful, but in some cases they might clutter the code and make it less readable. Once such case is inside a boolean expression, where a function expressions might cause the boolean expression be longer than the code which depends on its value.

Rule Details

This rule is aimed to flag usages of function expressions inside boolean expressions and suggest extracting them for better readability.

The following patterns are considered problems:

while (function(n) {/* something with n */}(i)) {
  i++
  // ...
}

if (arr.some(function(int) {
  return int > 2 && int % 2 === 0
})) {
  // ...
}

The following patterns are not considered problems:

function checkInt(n) {/* something with n */}

while (checkInt(i)) {
  i++
  // ...
}

function isEvenAndGreaterThanTwo(int) {
  return int > 2 && int % 2 === 0
}

if (arr.some(isEvenAndGreaterThanTwo)) {
  // ...
}

Version

This rule was introduced in eslint-plugin-wix-editor 1.0.0.