# oxc/bad-comparison-sequence

> Disallow chained comparisons such as `a < b < c`

`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.

{/* Generated by src/codegen/lint-rule-docs.ts. Do not edit this section. */}

## Configure

Off by default. To turn it on:

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

{/* End of the generated section. */}

## Examples

Reported:

{/* bad {"count": 2} */}
```js
if (min < value < max) {
  accept(value);
}

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

Not reported:

{/* good */}
```js
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;
```