oxc/bad-comparison-sequence

min < value < max doesn't test whether value is between the two. JavaScript evaluates min < value first, gets true or false, and compares that with max. 1 < 5 < 3 is true < 3, which is true. In the same way, a === b === c compares c with a boolean.

The rule reports two relational operators in a row (<, <=, >, >=) or two equality operators in a row (==, !=, ===, !==). A mix of both kinds, such as a < b === c < d, isn't reported. Neither is a left side in parentheses, because that shows you mean to compare the boolean.

Configure#

Off by default. To turn it on:

[lint.rules]
"oxc/bad-comparison-sequence" = "error" # or "warn"

Examples#

if (min < value < max) {
  accept(value);
}

const allEqual = width === height === depth;

if (min < value && value < max) {
  accept(value);
}

const allEqual = width === height && height === depth;
const sameAnswer = (left === expected) === (right === expected);
const sameDirection = start < end === from < to;