From f3b2f05bf8fc80ca20a2a5125a55868b3412e998 Mon Sep 17 00:00:00 2001
From: Nicholas Jamieson <nicholas@cartant.com>
Date: Tue, 16 Mar 2021 02:18:23 +1000
Subject: [PATCH] refactor: use n-args for startWith (#6114)

* refactor: use n-args for startWith

* chore: update api_guardian

* chore: add sigs for naughty devs

* chore: update api_guardian
---
 api_guard/dist/types/operators/index.d.ts | 12 ++----
 src/internal/operators/startWith.ts       | 45 +++++++----------------
 2 files changed, 17 insertions(+), 40 deletions(-)

diff --git a/api_guard/dist/types/operators/index.d.ts b/api_guard/dist/types/operators/index.d.ts
index ddd88940ad..7b3d888113 100644
--- a/api_guard/dist/types/operators/index.d.ts
+++ b/api_guard/dist/types/operators/index.d.ts
@@ -245,14 +245,10 @@ export declare function skipWhile<T>(predicate: BooleanConstructor): OperatorFun
 export declare function skipWhile<T>(predicate: (value: T, index: number) => true): OperatorFunction<T, never>;
 export declare function skipWhile<T>(predicate: (value: T, index: number) => boolean): MonoTypeOperatorFunction<T>;
 
-export declare function startWith<T>(scheduler: SchedulerLike): MonoTypeOperatorFunction<T>;
-export declare function startWith<T, D>(v1: D, scheduler: SchedulerLike): OperatorFunction<T, T | D>;
-export declare function startWith<T, D, E>(v1: D, v2: E, scheduler: SchedulerLike): OperatorFunction<T, T | D | E>;
-export declare function startWith<T, D, E, F>(v1: D, v2: E, v3: F, scheduler: SchedulerLike): OperatorFunction<T, T | D | E | F>;
-export declare function startWith<T, D, E, F, G>(v1: D, v2: E, v3: F, v4: G, scheduler: SchedulerLike): OperatorFunction<T, T | D | E | F | G>;
-export declare function startWith<T, D, E, F, G, H>(v1: D, v2: E, v3: F, v4: G, v5: H, scheduler: SchedulerLike): OperatorFunction<T, T | D | E | F | G | H>;
-export declare function startWith<T, D, E, F, G, H, I>(v1: D, v2: E, v3: F, v4: G, v5: H, v6: I, scheduler: SchedulerLike): OperatorFunction<T, T | D | E | F | G | H | I>;
-export declare function startWith<T, A extends any[] = T[]>(...values: A): OperatorFunction<T, T | ValueFromArray<A>>;
+export declare function startWith<T>(value: null): OperatorFunction<T, T | null>;
+export declare function startWith<T>(value: undefined): OperatorFunction<T, T | undefined>;
+export declare function startWith<T, A extends readonly unknown[] = T[]>(...valuesAndScheduler: [...A, SchedulerLike]): OperatorFunction<T, T | ValueFromArray<A>>;
+export declare function startWith<T, A extends readonly unknown[] = T[]>(...values: A): OperatorFunction<T, T | ValueFromArray<A>>;
 
 export declare function subscribeOn<T>(scheduler: SchedulerLike, delay?: number): MonoTypeOperatorFunction<T>;
 
diff --git a/src/internal/operators/startWith.ts b/src/internal/operators/startWith.ts
index 1b89fe700d..d5cab4ced5 100644
--- a/src/internal/operators/startWith.ts
+++ b/src/internal/operators/startWith.ts
@@ -1,40 +1,21 @@
 import { concat } from '../observable/concat';
-import { MonoTypeOperatorFunction, OperatorFunction, SchedulerLike, ValueFromArray } from '../types';
+import { OperatorFunction, SchedulerLike, ValueFromArray } from '../types';
 import { popScheduler } from '../util/args';
 import { operate } from '../util/lift';
 
-/* tslint:disable:max-line-length */
-/** @deprecated The scheduler argument is deprecated, use scheduled and concatAll. Details: https://rxjs.dev/deprecations/scheduler-argument */
-export function startWith<T>(scheduler: SchedulerLike): MonoTypeOperatorFunction<T>;
-/** @deprecated The scheduler argument is deprecated, use scheduled and concatAll. Details: https://rxjs.dev/deprecations/scheduler-argument */
-export function startWith<T, D>(v1: D, scheduler: SchedulerLike): OperatorFunction<T, T | D>;
-/** @deprecated The scheduler argument is deprecated, use scheduled and concatAll. Details: https://rxjs.dev/deprecations/scheduler-argument */
-export function startWith<T, D, E>(v1: D, v2: E, scheduler: SchedulerLike): OperatorFunction<T, T | D | E>;
-/** @deprecated The scheduler argument is deprecated, use scheduled and concatAll. Details: https://rxjs.dev/deprecations/scheduler-argument */
-export function startWith<T, D, E, F>(v1: D, v2: E, v3: F, scheduler: SchedulerLike): OperatorFunction<T, T | D | E | F>;
-/** @deprecated The scheduler argument is deprecated, use scheduled and concatAll. Details: https://rxjs.dev/deprecations/scheduler-argument */
-export function startWith<T, D, E, F, G>(v1: D, v2: E, v3: F, v4: G, scheduler: SchedulerLike): OperatorFunction<T, T | D | E | F | G>;
-/** @deprecated The scheduler argument is deprecated, use scheduled and concatAll. Details: https://rxjs.dev/deprecations/scheduler-argument */
-export function startWith<T, D, E, F, G, H>(
-  v1: D,
-  v2: E,
-  v3: F,
-  v4: G,
-  v5: H,
-  scheduler: SchedulerLike
-): OperatorFunction<T, T | D | E | F | G | H>;
-/** @deprecated The scheduler argument is deprecated, use scheduled and concatAll. Details: https://rxjs.dev/deprecations/scheduler-argument */
-export function startWith<T, D, E, F, G, H, I>(
-  v1: D,
-  v2: E,
-  v3: F,
-  v4: G,
-  v5: H,
-  v6: I,
-  scheduler: SchedulerLike
-): OperatorFunction<T, T | D | E | F | G | H | I>;
+// Devs are more likely to pass null or undefined than they are a scheduler
+// without accompanying values. To make things easier for (naughty) devs who
+// use the `strictNullChecks: false` TypeScript compiler option, these
+// overloads with explicit null and undefined values are included.
 
-export function startWith<T, A extends any[] = T[]>(...values: A): OperatorFunction<T, T | ValueFromArray<A>>;
+export function startWith<T>(value: null): OperatorFunction<T, T | null>;
+export function startWith<T>(value: undefined): OperatorFunction<T, T | undefined>;
+
+/** @deprecated The scheduler argument is deprecated, use scheduled and concatAll. Details: https://rxjs.dev/deprecations/scheduler-argument */
+export function startWith<T, A extends readonly unknown[] = T[]>(
+  ...valuesAndScheduler: [...A, SchedulerLike]
+): OperatorFunction<T, T | ValueFromArray<A>>;
+export function startWith<T, A extends readonly unknown[] = T[]>(...values: A): OperatorFunction<T, T | ValueFromArray<A>>;
 
 /**
  * Returns an observable that, at the moment of subscription, will synchronously emit all