RecordEmpty.ts

let zz: {}
zz = {} // COMPILES
zz = 1 // COMPILES
zz = "1" // COMPILES
zz = true // COMPILES
zz = { ff:true } // COMPILES
zz = [11] // COMPILES
zz = [] // COMPILES
zz = null // ERROR: Type 'null' is not assignable to type '{}'.(2322)
zz = undefined // ERROR: Type 'undefined' is not assignable to type '{}'.(2322)


type RecordEmpty = Record<string,never>

let kk: RecordEmpty
kk = {} // COMPILES
kk = 1 // ERROR: Type 'number' is not assignable to type 'Record<string, never>'.(2322)
kk = "1" // ERROR: Type 'string' is not assignable to type 'Record<string, never>'.(2322)
kk = true // ERROR: Type 'boolean' is not assignable to type 'Record<string, never>'.(2322)
kk = { ff: true } // ERROR: Type 'boolean' is not assignable to type 'never'.(2322)
kk = [11] // ERROR: Type 'number' is not assignable to type 'never'.(2322)
kk = [] // ERROR: Type 'never[]' is not assignable to type 'RecordEmpty'. Index signature is missing in type 'never[]'.(2322)
kk = null // ERROR: Type 'null' is not assignable to type 'RecordEmpty'.(2322)
kk = undefined // ERROR: Type 'undefined' is not assignable to type 'RecordEmpty'.(2322)


declare let r0: {}
declare let r1: Omit<{a:never},"a">
declare let r2: Record<never,never>
declare let r3: RecordEmpty

if(typeof r0 === "number") { r0 } // r0: number
if(typeof r1 === "number") { r1 } // r1: number
if(typeof r2 === "number") { r2 } // r2: number
if(typeof r3 === "number") { r3 } // r3: never

r0 = 1 // COMPILES
r1 = 1 // COMPILES
r2 = 1 // COMPILES
r3 = 1 // ERROR: Type 'number' is not assignable to type 'Record<string,never>'.(2322)



/**
 * A better alternative to type `{}`.
 *
 * When using `{}` you might think that it's just an empty Record,
 * but in reality it it's just any nullable type see:
 * ```ts
 * let zz: {}
 * zz = {} // COMPILES
 * zz = 1 // COMPILES
 * zz = "1" // COMPILES
 * zz = true // COMPILES
 * zz = { ff:true } // COMPILES
 * zz = [11] // COMPILES
 * zz = [] // COMPILES
 * zz = null // ERROR: Type 'null' is not assignable to type '{}'.(2322)
 * zz = undefined // ERROR: Type 'undefined' is not assignable to type '{}'.(2322)
 * ```
 *
 * vs:
 *
 * ```ts
 * let kk: RecordEmpty
 * kk = {} // COMPILES
 * kk = 1 // ERROR: Type 'number' is not assignable to type 'Record<string, never>'.(2322)
 * kk = "1" // ERROR: Type 'string' is not assignable to type 'Record<string, never>'.(2322)
 * kk = true // ERROR: Type 'boolean' is not assignable to type 'Record<string, never>'.(2322)
 * kk = { ff: true } // ERROR: Type 'boolean' is not assignable to type 'never'.(2322)
 * kk = [11] // ERROR: Type 'number' is not assignable to type 'never'.(2322)
 * kk = [] // ERROR: Type 'never[]' is not assignable to type 'RecordEmpty'. Index signature is missing in type 'never[]'.(2322)
 * kk = null // ERROR: Type 'null' is not assignable to type 'RecordEmpty'.(2322)
 * kk = undefined // ERROR: Type 'undefined' is not assignable to type 'RecordEmpty'.(2322)
 * ```
 * export type RecordEmpty = Record<string, never>;
 */