fix(typings): Fix optional predicate typings for user-defined typeguard predicates

Author: trxcllnt

src/add/asynciterable-operators/first.ts

@@ -7,7 +7,7 @@ import { first } from '../../asynciterable/first';
 
 export function firstProto<T, S extends T>(
   this: AsyncIterableX<T>,
-  predicate?: (value: T, index: number) => value is S
+  predicate: (value: T, index: number) => value is S
 ): Promise<S | undefined>;
 export function firstProto<T>(
   this: AsyncIterableX<T>,

src/add/asynciterable-operators/last.ts

@@ -7,7 +7,7 @@ import { last } from '../../asynciterable/last';
 
 export function lastProto<T, S extends T>(
   this: AsyncIterableX<T>,
-  predicate?: (value: T, index: number) => value is S
+  predicate: (value: T, index: number) => value is S
 ): Promise<S | undefined>;
 export function lastProto<T>(
   this: AsyncIterableX<T>,

src/add/asynciterable-operators/single.ts

@@ -7,7 +7,7 @@ import { single } from '../../asynciterable/single';
 
 export function singleProto<T, S extends T>(
   this: AsyncIterableX<T>,
-  predicate?: (value: T, index: number) => value is S
+  predicate: (value: T, index: number) => value is S
 ): Promise<S | undefined>;
 export function singleProto<T>(
   this: AsyncIterableX<T>,

src/add/iterable-operators/first.ts

@@ -7,7 +7,7 @@ import { first } from '../../iterable/first';
 
 export function firstProto<T, S extends T>(
   this: IterableX<T>,
-  predicate?: (value: T, index: number) => value is S
+  predicate: (value: T, index: number) => value is S
 ): S | undefined;
 export function firstProto<T>(
   this: IterableX<T>,

src/add/iterable-operators/last.ts

@@ -6,7 +6,7 @@ import { last } from '../../iterable/last';
  */
 export function lastProto<T, S extends T>(
   this: IterableX<T>,
-  predicate?: (value: T, index: number) => value is S
+  predicate: (value: T, index: number) => value is S
 ): S | undefined;
 export function lastProto<T>(
   this: IterableX<T>,

src/add/iterable-operators/single.ts

@@ -6,7 +6,7 @@ import { single } from '../../iterable/single';
  */
 export function singleProto<T, S extends T>(
   this: IterableX<T>,
-  predicate?: (value: T, index: number) => value is S
+  predicate: (value: T, index: number) => value is S
 ): S | undefined;
 export function singleProto<T>(
   this: IterableX<T>,

src/asynciterable/first.ts

@@ -1,6 +1,6 @@
 export async function first<T, S extends T>(
   source: AsyncIterable<T>,
-  predicate?: (value: T, index: number) => value is S
+  predicate: (value: T, index: number) => value is S
 ): Promise<S | undefined>;
 export async function first<T>(
   source: AsyncIterable<T>,

src/asynciterable/last.ts

@@ -1,6 +1,6 @@
 export async function last<T, S extends T>(
   source: AsyncIterable<T>,
-  predicate?: (value: T, index: number) => value is S
+  predicate: (value: T, index: number) => value is S
 ): Promise<S | undefined>;
 export async function last<T>(
   source: AsyncIterable<T>,

src/asynciterable/single.ts

@@ -1,6 +1,6 @@
 export async function single<T, S extends T>(
   source: AsyncIterable<T>,
-  predicate?: (value: T, index: number) => value is S
+  predicate: (value: T, index: number) => value is S
 ): Promise<S | undefined>;
 export async function single<T>(
   source: AsyncIterable<T>,

src/iterable/first.ts

@@ -9,7 +9,7 @@
  */
 export function first<T, S extends T>(
   source: Iterable<T>,
-  predicate?: (value: T, index: number) => value is S
+  predicate: (value: T, index: number) => value is S
 ): S | undefined;
 export function first<T>(
   source: Iterable<T>,