# The `!` operator

## Returns correct result when used on a `Boolean`

### Juttle

    emit -from Date.new(0) -limit 1
      | put f = !false
      | put t = !true
      | view result

### Output

    { "time": "1970-01-01T00:00:00.000Z", f: true, t: false }

## Produces an error when used on operand of invalid type

### Juttle

    emit -from Date.new(0) -limit 1 | put result = !null | view result

### Errors

  * "!" operator: Invalid operand type (null).

## Produces an error when used on a string literal

Regression test for #650.

### Juttle

    emit -from Date.new(0) -limit 1 | put result = !'abcd' | view result

### Errors

  * "!" operator: Invalid operand type (string).