# And

`type` in `services` · v0.7.1

<https://docs.seedcord.org/packages/services/0.7.1/types/and>

Returns a boolean for whether two given types are both `true`.

Use-case: Constructing complex conditional types where multiple conditions must be satisfied.

## Examples

```ts
import type {And} from 'type-fest';

type TT = And<true, true>;
//=> true

type TF = And<true, false>;
//=> false

type FT = And<false, true>;
//=> false

type FF = And<false, false>;
//=> false

Note: When boolean is passed as an argument, it is distributed into separate cases, and the final result is a union of those cases. For example, And<true, boolean> expands to And<true, true> | And<true, false>, which simplifies to true | false (i.e., boolean).
```

```ts
import type {And} from 'type-fest';

type A = And<true, boolean>;
//=> boolean

type B = And<boolean, true>;
//=> boolean

type C = And<false, boolean>;
//=> false

type D = And<boolean, false>;
//=> false

type E = And<boolean, boolean>;
//=> boolean

Note: If either of the types is never, the result becomes false.
```

```ts
import type {And} from 'type-fest';

type A = And<true, never>;
//=> false

type B = And<never, true>;
//=> false

type C = And<false, never>;
//=> false

type D = And<never, false>;
//=> false

type E = And<boolean, never>;
//=> false

type F = And<never, boolean>;
//=> false

type G = And<never, never>;
//=> false
```

## Declaration

```ts
type And<
    A extends boolean,
    B extends boolean
> = AndAll<[A, B]>;
```

## See also

- AndAll
- Or
- Xor