Add typescript@rc to test for typescript@5.4 (#500)

## Summary
<!-- Succinctly describe your change, providing context, what you've
changed, and why. -->

Adds `typescript@rc` (currently `typescript@5.4.0`). This is used to
test the 5.4 release candidate to resolve any issues before it ships.
When it does, we'll move this PR to target `typescript@5.4.0` and merge,
including a changeset if any changes needed to be made.

We should ship this change once the final build is submitted at the
beginning of March. See microsoft/TypeScript#56948

## Checklist
<!-- Tick these items off as you progress. -->
<!-- If an item isn't applicable, ideally please strikeout the item by
wrapping it in "~~"" and suffix it with "N/A My reason for skipping
this." -->
<!-- e.g. "- [ ] ~~Added tests~~ N/A Only touches docs" -->

- [ ] ~Added a [docs PR](https://github.com/inngest/website) that
references this PR~ N/A
- [x] Added unit/integration tests
- [x] Added changesets if applicable

## Related

- microsoft/TypeScript#56948

.changeset/forty-poems-invite.md

@@ -0,0 +1,5 @@
+---
+"inngest": patch
+---
+
+Add support for `typescript@5.4`

.github/workflows/pr.yml

@@ -50,6 +50,7 @@ jobs:
       matrix:
         tsVersion:
          - 'latest'
+         - 'rc'
          - '~5.3.0'
          - '~5.2.0'
          - '~5.1.0'

packages/inngest/package.json

@@ -180,7 +180,6 @@
     "ms": "^2.1.3",
     "serialize-error-cjs": "^0.1.3",
     "strip-ansi": "^5.2.0",
-    "type-fest": "^3.13.1",
     "type-plus": "^5.1.0",
     "zod": "~3.22.3"
   },

packages/inngest/src/components/EventSchemas.ts

@@ -1,6 +1,9 @@
-import { type Simplify } from "type-fest";
 import { type internalEvents } from "../helpers/consts";
-import { type IsEmptyObject, type IsStringLiteral } from "../helpers/types";
+import {
+  type IsEmptyObject,
+  type IsStringLiteral,
+  type Simplify,
+} from "../helpers/types";
 import type * as z from "../helpers/validators/zod";
 import {
   type EventPayload,

packages/inngest/src/components/Inngest.ts

@@ -1,5 +1,4 @@
-import { type IfNever, type Jsonify } from "type-fest";
-import { type SimplifyDeep } from "type-fest/source/merge-deep";
+import { type IsNever } from "type-plus";
 import { InngestApi } from "../api/api";
 import {
   defaultDevServerHost,
@@ -18,10 +17,12 @@ import {
   type Mode,
 } from "../helpers/env";
 import { fixEventKeyMissingSteps, prettyError } from "../helpers/errors";
+import { type Jsonify } from "../helpers/jsonify";
 import { stringify } from "../helpers/strings";
 import {
   type ExclusiveKeys,
   type SendEventPayload,
+  type SimplifyDeep,
   type WithoutInternal,
 } from "../helpers/types";
 import { DefaultLogger, ProxyLogger, type Logger } from "../middleware/logger";
@@ -817,11 +818,9 @@ export type GetFunctionOutputFromInngestFunction<
   TFunction extends InngestFunction.Any,
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
 > = TFunction extends InngestFunction<any, any, any, any, infer IHandler>
-  ? IfNever<
-      SimplifyDeep<Jsonify<Awaited<ReturnType<IHandler>>>>,
-      null,
-      SimplifyDeep<Jsonify<Awaited<ReturnType<IHandler>>>>
-    >
+  ? IsNever<SimplifyDeep<Jsonify<ReturnType<IHandler>>>> extends true
+    ? null
+    : SimplifyDeep<Jsonify<ReturnType<IHandler>>>
   : unknown;
 
 /**
@@ -837,11 +836,9 @@ export type GetFunctionOutputFromReferenceInngestFunction<
   TFunction extends InngestFunctionReference.Any,
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
 > = TFunction extends InngestFunctionReference<any, infer IOutput>
-  ? IfNever<
-      SimplifyDeep<Jsonify<IOutput>>,
-      null,
-      SimplifyDeep<Jsonify<IOutput>>
-    >
+  ? IsNever<SimplifyDeep<Jsonify<IOutput>>> extends true
+    ? null
+    : SimplifyDeep<Jsonify<IOutput>>
   : unknown;
 
 /**

packages/inngest/src/components/InngestFunction.test.ts

@@ -40,8 +40,7 @@ import {
   type OutgoingOp,
 } from "@local/types";
 import { fromPartial } from "@total-typescript/shoehorn";
-import { type IsEqual } from "type-fest";
-import { assertType } from "type-plus";
+import { assertType, type IsEqual } from "type-plus";
 import { createClient, runFnWithStack } from "../test/helpers";
 
 type TestEvents = {

packages/inngest/src/components/InngestFunctionReference.ts

@@ -1,5 +1,4 @@
-import { type Simplify } from "type-fest";
-import { type IsAny } from "../helpers/types";
+import { type IsAny, type Simplify } from "../helpers/types";
 import {
   type ResolveSchema,
   type ValidSchemaInput,

packages/inngest/src/components/InngestMiddleware.test.ts

@@ -4,8 +4,8 @@ import { ExecutionVersion } from "@local/components/execution/InngestExecution";
 import { Inngest } from "@local/components/Inngest";
 import { referenceFunction } from "@local/components/InngestFunctionReference";
 import { InngestMiddleware } from "@local/components/InngestMiddleware";
+import { type IsUnknown } from "@local/helpers/types";
 import { StepOpCode } from "@local/types";
-import { type IsUnknown } from "type-fest";
 import { assertType, type IsEqual } from "type-plus";
 import { createClient, runFnWithStack, testClientId } from "../test/helpers";
 

packages/inngest/src/components/InngestMiddleware.ts

@@ -1,10 +1,10 @@
-import { type Simplify } from "type-fest";
 import { cacheFn, waterfall } from "../helpers/functions";
 import {
   type Await,
   type MaybePromise,
   type ObjectAssign,
   type PartialK,
+  type Simplify,
 } from "../helpers/types";
 import {
   type BaseContext,

packages/inngest/src/components/InngestStepTools.test.ts

@@ -10,8 +10,7 @@ import {
   type InvocationResult,
 } from "@local/types";
 import ms from "ms";
-import { type IsEqual } from "type-fest";
-import { assertType } from "type-plus";
+import { assertType, type IsEqual } from "type-plus";
 import { z } from "zod";
 import {
   createClient,

packages/inngest/src/components/InngestStepTools.ts

@@ -1,13 +1,13 @@
-import { type Jsonify } from "type-fest";
-import { type SimplifyDeep } from "type-fest/source/merge-deep";
 import { z } from "zod";
 import { logPrefix } from "../helpers/consts";
+import { type Jsonify } from "../helpers/jsonify";
 import { timeStr } from "../helpers/strings";
 import {
   type ExclusiveKeys,
   type ObjectPaths,
   type ParametersExceptFirst,
   type SendEventPayload,
+  type SimplifyDeep,
 } from "../helpers/types";
 import {
   StepOpCode,

packages/inngest/src/components/execution/InngestExecution.ts

@@ -1,8 +1,8 @@
 import Debug, { type Debugger } from "debug";
-import { type Simplify } from "type-fest";
 import { type MaybePromise } from "type-plus";
 import { type ServerTiming } from "../../helpers/ServerTiming";
 import { debugPrefix } from "../../helpers/consts";
+import { type Simplify } from "../../helpers/types";
 import { type Context, type IncomingOp, type OutgoingOp } from "../../types";
 import { type Inngest } from "../Inngest";
 import { type ActionResponse } from "../InngestCommHandler";

packages/inngest/src/components/execution/v1.ts

@@ -1,5 +1,4 @@
 import { sha1 } from "hash.js";
-import { type Simplify } from "type-fest";
 import { z } from "zod";
 import { internalEvents } from "../../helpers/consts";
 import {
@@ -16,7 +15,7 @@ import {
   resolveAfterPending,
   runAsPromise,
 } from "../../helpers/promises";
-import { type MaybePromise } from "../../helpers/types";
+import { type MaybePromise, type Simplify } from "../../helpers/types";
 import {
   StepOpCode,
   failureEventErrorSchema,