SetParameterType: Fix compatibility with TypeScript 5.4 (#835)

Co-authored-by: Sindre Sorhus <sindresorhus@gmail.com>

source/set-parameter-type.d.ts

@@ -1,17 +1,53 @@
 import type {IsUnknown} from './is-unknown';
+import type {StaticPartOfArray} from './internal';
+import type {UnknownArray} from './unknown-array';
 
 /**
-Create a tuple that replaces the given `Tuple`'s elements with the given `Record_`'s values at the given indices.
+Create an array that replaces the given `TArray`'s elements with the given `TObject`'s values at the given indices.
+
+`TArray` and `TObject` supports tailing spread array like `[string, ...boolean[]]`, but does not support `[string, ...boolean[], number]`.
+
+@example:
+```ts
+// object
+type A = MergeObjectToArray<[string, number], {0: boolean}>;
+//=> [boolean, number]
+
+// array
+type B = MergeObjectToArray<[string, number], [boolean]>;
+//=> [boolean, number]
+
+// tailing spread array
+type C = MergeObjectToArray<[string, ...boolean[]], {1: number}>;
+//=> [string, ...number[]]
+
+type D = MergeObjectToArray<[string, ...boolean[]], [number, ...string[]]>;
+//=> [number, ...string[]]
+```
 */
-type MergeObjectToTuple<Tuple extends unknown[], Record_ extends Record<number, unknown>> = {
-	[K in keyof Tuple]: Record_ extends Record<string, unknown>
-		// Handle object case like `{0: string, 1: number}`
-		? K extends `${infer NumberK extends number}`
-			? NumberK extends keyof Record_ ? Record_[K] : Tuple[K]
-			: never // Should not happen
-		// Handle tuple case like `[string, number]`
-		: K extends keyof Record_ ? Record_[K] : Tuple[K]
-};
+type MergeObjectToArray<TArray extends UnknownArray, TObject, TArrayCopy extends UnknownArray = TArray> =
+	// If `TObject` is an array like `[0, 1, 2]`
+	TObject extends UnknownArray
+		// If `TObject` is a variable length array, we should use `TObject`'s type as the result type.
+		? number extends TObject['length']
+			? TObject
+			: {
+				[K in keyof TArray]: K extends keyof TObject ? TObject[K] : TArray[K]
+			}
+		: TObject extends object
+			// If `TObject` is a object witch key is number like `{0: string, 1: number}`
+			? {
+				[K in keyof TArray]:
+				K extends `${infer NumberK extends number}`
+					? NumberK extends keyof TObject ? TObject[NumberK] : TArray[K]
+					: number extends K
+					// If array key `K` is `number`, means it's a rest parameter, we should set the rest parameter type to corresponding type in `TObject`.
+					// example: `MergeObjectToParamterArray<[string, ...boolean[]], {1: number}>` => `[string, ...number[]]`
+						? StaticPartOfArray<TArrayCopy>['length'] extends keyof TObject
+							? TObject[StaticPartOfArray<TArrayCopy>['length']]
+							: TArray[K]
+						: never
+			} : never;
 
 /**
 Create a function that replaces some parameters with the given parameters.
@@ -39,7 +75,7 @@ Use-case:
 ```
 import type {SetParameterType} from 'type-fest';
 
-type HandleMessage = (data: Data, message: string) => void;
+type HandleMessage = (data: Data, message: string, ...arguments: any[]) => void;
 
 type HandleOk = SetParameterType<HandleMessage, {0: SuccessData, 1: 'ok'}>;
 //=> type HandleOk = (data: SuccessData, message: 'ok') => void;
@@ -48,9 +84,19 @@ type HandleOk = SetParameterType<HandleMessage, {0: SuccessData, 1: 'ok'}>;
 type HandleError = SetParameterType<HandleMessage, [data: ErrorData, message: 'error']>;
 //=> type HandleError = (data: ErrorData, message: 'error') => void;
 
-// Could change single parameter type.
+// Change single parameter type.
 type HandleWarn = SetParameterType<HandleMessage, {1: 'warn'}>;
 //=> type HandleWarn = (data: Data, message: 'warn') => void;
+
+// Change rest parameter type.
+
+// Way 1: Input full parameter type.
+type HandleLog = SetParameterType<HandleMessage, [data: Data, message: 'log', ...arguments: string[]]>;
+//=> type HandleLog = (data: Data, message: 'log', ...arguments: string[]) => void;
+
+// Way 2: Input rest parameter type by Object index.
+type HandleLog2 = SetParameterType<HandleMessage, {2: string}>;
+//=> type HandleLog2 = (data: Data, message: string, ...arguments: string[]) => void;
 ```
 
 @category Function
@@ -62,7 +108,7 @@ export type SetParameterType<Fn extends (...arguments_: any[]) => unknown, P ext
 			// If a function did not specify the `this` fake parameter, it will be inferred to `unknown`.
 			// We want to detect this situation just to display a friendlier type upon hovering on an IntelliSense-powered IDE.
 			IsUnknown<ThisArg> extends true
-				? (...arguments_: MergeObjectToTuple<Arguments, P>) => ReturnType<Fn>
-				: (this: ThisArg, ...arguments_: MergeObjectToTuple<Arguments, P>) => ReturnType<Fn>
+				? (...arguments_: MergeObjectToArray<Arguments, P>) => ReturnType<Fn>
+				: (this: ThisArg, ...arguments_: MergeObjectToArray<Arguments, P>) => ReturnType<Fn>
 		)
 		: Fn;	// This part should be unreachable

test-d/set-parameter-type.ts

@@ -1,5 +1,5 @@
 import {expectType} from 'tsd';
-import {type SetParameterType} from '../index';
+import type {SetParameterType} from '../index';
 
 function fn(_a: number, _b: string, _c: Object, ..._arguments: boolean[]) {
 	return null;
@@ -27,9 +27,13 @@ expectType<(a: string, b: boolean, c: Object, ...args: boolean[]) => null>(test3
 test3('1', true, {}, true);
 
 // Test `...args` parameter
-declare const test4: SetParameterType<typeof fn, {3: string}>;
-expectType<(a: number, b: string, c: Object, ...args: string[]) => null>(test4);
-test4(1, '1', {}, '1');
+declare const testargs: SetParameterType<typeof fn, {3: string}>;
+expectType<(a: number, b: string, c: Object, ...args: string[]) => null>(testargs);
+testargs(1, '1', {}, '1');
+
+declare const testargs2: SetParameterType<typeof fn, [string, number, number, ...boolean[]]>;
+expectType<(a: string, b: number, c: number, ...args: boolean[]) => null>(testargs2);
+testargs2('1', 1, 1, true);
 
 // Test arrow function
 declare const test5: SetParameterType<typeof arrowFunction, {0: string}>;