UNPKG

mobx-keystone-mindreframer

Version:

A MobX powered state management solution based on data trees with first class support for Typescript, snapshots, patches and much more

mobx-keystone.js.org

xaviergonz/mobx-keystone

32 lines (29 loc) • 926 B
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
/** * @ignore * * A primitive value. */ export type PrimitiveValue = undefined | null | boolean | number | string | bigint /** * @ignore * * Checks if a value is optional (undefined, any or unknown). * * Examples: * - string = false * - undefined = true * - string | undefined = true * - string & undefined = false, but we don't care * - any = true * - unknown = true * - null = false * - string | null = false * - string & null = false */ export type IsOptionalValue<C, TV, FV> = undefined extends C ? TV : FV // type _A = IsOptionalValue<string, true, false> // false // type _B = IsOptionalValue<undefined, true, false> // true // type _C = IsOptionalValue<string | undefined, true, false> // true // type _D = IsOptionalValue<string & undefined, true, false> // false, but we don't care // type _E = IsOptionalValue<any, true, false> // true // type _F = IsOptionalValue<unknown, true, false> // true