updated init and tail typings

types/init.d.ts

@@ -1,2 +1,10 @@
+// string
 export function init(list: string): string;
-export function init<T>(list: readonly T[]): T[];
+// empty tuple - purposefully `never, They literally have no init
+export function tail(list: readonly []): never;
+// length=1 tuples also return `never`. They literally have no init
+export function init<T>(list: readonly [T]): never;
+// non-empty tuples and array
+// `infer Init` only works on types like `readonly [1, '2', 3]` where you will get back `['2', 3]`
+// else, if the type is `string[]`, you'll get back `string[]`
+export function init<T extends readonly [...any]>(list: T): T extends readonly [...infer Init, any] ? Init : T;

types/tail.d.ts

@@ -5,6 +5,6 @@ export function tail(list: readonly []): never;
 // length=1 tuples also return `never`. They literally have no tail
 export function tail<T>(list: readonly [T]): never;
 // non-empty tuples and array
-// `infer Rest` only works on types like `readonly [1, '2', 3]` where you will get back `['2', 3]`
+// `infer Tail` only works on types like `readonly [1, '2', 3]` where you will get back `['2', 3]`
 // else, if the type is `string[]`, you'll get back `string[]`
-export function tail<T extends readonly [...any]>(tuple: T): T extends readonly [any, ...infer Rest] ? Rest : T;
+export function tail<T extends readonly [...any]>(list: T): T extends readonly [any, ...infer Tail] ? Tail : T;