# Function: pre()

> > **pre**(`expectTruthy`): `asserts expectTruthy`

# Function: pre()

> **pre**(`expectTruthy`): `asserts expectTruthy`

Defined in: [packages/fast-check/src/check/precondition/Pre.ts:9](https://github.com/dubzzz/fast-check/blob/4663db899d411b24434189b8e560b5ecefc93f23/packages/fast-check/src/check/precondition/Pre.ts#L9)

Add pre-condition checks inside a property execution

## Parameters

| Parameter | Type | Description |
| ------ | ------ | ------ |
| `expectTruthy` | `boolean` | cancel the run whenever this value is falsy |

## Returns

`asserts expectTruthy`

## Remarks

Since 1.3.0