# oxc/bad-bitwise-operator

> Disallow `&` and `|` where `&&` and `||` were probably meant

`&` and `|` are one keystroke away from `&&` and `||`, and the code still runs. They convert both sides to 32-bit integers, so `"Ann" | "guest"` is `0`, not a name. They also evaluate both sides every time, so `user & user.city` throws when `user` is `undefined`.

The rule reports three shapes:

- `user & user.city`: a variable, with a property of that variable on the right.
- `title | "Untitled"`: a variable, with something that clearly isn't a number on the right.
- `title |= "Untitled"`: the same for `|=`.

A number, a variable, `null` and arithmetic can be numbers, so they're allowed on the right. A string, an object, an array, `typeof x`, `!x`, a call and a property access are reported.

`--fix-suggestions` replaces the operator with the logical one.

{/* 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-bitwise-operator" = "error" # or "warn"
```

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

## Examples

Reported:

{/* bad {"count": 3} */}
```js
const city = user & user.city;
const label = title | "Untitled";
options |= {};
```

Not reported:

{/* good */}
```js
const city = user && user.city;
const label = title || "Untitled";
options ||= {};

const mode = flags | 4;
const both = read | write;
```

## When not to use it

Code that combines flags is reported when the right side is a property or a call, even though `|` is what you mean. Leave the rule off in that code.

{/* bad */}
```js
const mode = flags | Mode.Write;
```