> For the complete documentation index, see [llms.txt](https://docs.activejs.dev/activejs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.activejs.dev/activejs/fundamentals/units/boolunit.md).

# BoolUnit

**BoolUnit** is a type of [Unit](/activejs/fundamentals/units.md) that only accepts `boolean` data type as its value. It ensures that at any point of time the value would always be `boolean`.

It implements non-deprecated [Object.prototype](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object) methods like `toString`
 and redirects them to the stored `boolean` value inside the Unit, so when you call `BoolUnit.toString()` , it'll be executed on the Unit's value instead of the BoolUnit instance itself. Similarly, when you call other `Object.prototype` methods they are called on the stored value instead of BoolUnit instance.

See [API reference](https://api.activejs.dev/classes/boolunit) for more details.

|                 |           |
| --------------- | --------- |
| Default value   | `false`   |
| Value data type | `boolean` |

### BoolUnit vs `boolean`

BoolUnit can not be used as a drop-in replacement for primitive `boolean` value, since BoolUnit is a non-primitive data structure, and the actual `boolean` value is stored inside the Unit. See the below comparisons for more clarity.

```typescript
// initialization
let bool = false; // a variable with prmitive boolean value
const unit = new BoolUnit({initialValue: false});
// initialValue is optional, BoolUnit has false as default value

bool === unit // false
bool === unit.value() // true

unit + '' // 'false'
unit + 1 // 1, because false is converted to 0
unit.dispatch(true);
unit + 1 // 2, because true is converted to 1

typeof bool === 'boolean' // true
typeof unit === 'object' // true
typeof unit.value() === 'boolean' // true

// value assignment
bool = true;
unit.dispatch(true);

// value access
console.log(bool) // logs true
console.log(unit.value()) // logs true
// or
unit.subscribe(value => console.log(value)) // logs true, will log future values
```