🐛 Improve type inference

Closes #112

api.ts

@@ -24,7 +24,7 @@ const api: Api = {
     lodash: 'entries'
   },
   F: LAMBDAS,
-  first: {
+  head: {
     ramda: 'head',
     rambda: 'head',
     lodash: 'first'
@@ -37,7 +37,7 @@ const api: Api = {
   gt: ['ramda', 'lodash'],
   gte: ['ramda', 'lodash'],
   has: ALL_MODULES,
-  head: {
+  init: {
     rambda: 'init',
     ramda: 'init',
     lodash: 'initial'

mod.ts

@@ -22,12 +22,14 @@ export { gt } from './src/gt.ts'
 export { gte } from './src/gte.ts'
 export { has } from './src/has.ts'
 export { hasPath } from './src/hasPath.ts'
+export type { Head } from './src/head.ts'
 export { head } from './src/head.ts'
 export { identity } from './src/identity.ts'
 export { ifElse } from './src/ifElse.ts'
 export { ifElseFn } from './src/ifElseFn.ts'
 export { inc } from './src/inc.ts'
 export { includes } from './src/includes.ts'
+export { init } from './src/init.ts'
 export { isArray } from './src/isArray.ts'
 export { isBigint } from './src/isBigint.ts'
 export { isBoolean } from './src/isBoolean.ts'

src/last.ts

@@ -37,13 +37,11 @@ type Last<T extends string | readonly unknown[]> = T extends ''
   ? String2Array<T> extends []
     ? string
     : [never, ...String2Array<T>][String2Array<T>['length']]
-  : T extends never[] | readonly never[]
+  : T extends never[] | []
   ? undefined
-  : T extends unknown[] | readonly unknown[]
-  ? [never, ...T][T['length']]
-  : T extends string
-  ? string
-  : never
+  : T extends readonly [...infer _, infer L]
+  ? L
+  : T[T['length']] | undefined
 
 /**
  * Returns the last element of the given list or string.

test/last.test.ts

@@ -48,8 +48,8 @@ Deno.test('last', () => {
 Deno.test('Last', () => {
   assertEqual<undefined, Last<[] | never[] | readonly [] | readonly never[]>>()
   assertEqual<'', Last<[''] | readonly ['']>>()
-  assertEqual<string, Last<string[]>>()
-  assertEqual<string | number, Last<string | number[]>>()
+  assertEqual<string | undefined, Last<string[]>>()
+  assertEqual<string | number | undefined, Last<string | number[]>>()
   assertEqual<[], Last<[100, 200, 'hello', []]>>()
   assertEqual<string, Last<string>>()
   assertEqual<'', Last<''>>()