Or

import type {Or} from 'type-fest';

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

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

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

type FF = Or<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, Or<false, boolean> expands to Or<false, true> | Or<false, false>, which simplifies to true | false (i.e., boolean).

import type {Or} from 'type-fest';

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

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

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

type FF = Or<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, Or<false, boolean> expands to Or<false, true> | Or<false, false>, which simplifies to true | false (i.e., boolean).

import type {Or} from 'type-fest';

type A = Or<false, boolean>;
//=> boolean

type B = Or<boolean, false>;
//=> boolean

type C = Or<true, boolean>;
//=> true

type D = Or<boolean, true>;
//=> true

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

Note: If never is passed as an argument, it is treated as false and the result is computed accordingly.

import type {Or} from 'type-fest';

type A = Or<false, boolean>;
//=> boolean

type B = Or<boolean, false>;
//=> boolean

type C = Or<true, boolean>;
//=> true

type D = Or<boolean, true>;
//=> true

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

Note: If never is passed as an argument, it is treated as false and the result is computed accordingly.

import type {Or} from 'type-fest';

type A = Or<true, never>;
//=> true

type B = Or<never, true>;
//=> true

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

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

type E = Or<boolean, never>;
//=> boolean

type F = Or<never, boolean>;
//=> boolean

type G = Or<never, never>;
//=> false

import type {Or} from 'type-fest';

type A = Or<true, never>;
//=> true

type B = Or<never, true>;
//=> true

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

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

type E = Or<boolean, never>;
//=> boolean

type F = Or<never, boolean>;
//=> boolean

type G = Or<never, never>;
//=> false