feat: improve type safety

stdlib-js · Oct 14, 2024 · ce44167 · ce44167
1 parent 2b2dd25
commit ce44167
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diff --git a/lib/node_modules/@stdlib/utils/map-arguments/docs/types/index.d.ts b/lib/node_modules/@stdlib/utils/map-arguments/docs/types/index.d.ts
@@ -47,7 +47,57 @@
 * var out = bar( 1, 2, 3 );
 * // returns [ 2, 4, 6 ]
 */
-declare function mapArguments<T = unknown>( fcn: ( ...args: Array<T> ) => Array<T>, clbk: ( arg: T ) => T, thisArg?: unknown ): ( ...args: Array<T> ) => Array<T>;
+declare function mapArguments<
+	T extends ( ...args: Array<any> ) => any,
+	C extends ( this: ThisParameterType<T>, value: Parameters<T>[number], index: number ) => any
+>(
+	fcn: T,
+	clbk: C
+): ( ...args: Parameters<T> ) => ReturnType<T>;
+
+/**
+* Returns a function that applies arguments to a provided function after transforming arguments according to a callback function.
+*
+* ## Notes
+*
+* -   The callback function is provided the following arguments:
+*
+*     -   **value**: argument value.
+*     -   **index**: argument index.
+*
+* @param fcn - input function
+* @param clbk - callback function
+* @param thisArg - input function context
+* @returns function wrapper
+*
+* @example
+* function foo( a, b, c ) {
+*     return [ a, b, c ];
+* }
+*
+* function clbk( v ) {
+*     this.count += 1;
+*     return v * 2;
+* }
+*
+* var thisArg = { 'count': 0 };
+* var bar = mapArguments( foo, clbk, thisArg );
+*
+* var out = bar( 1, 2, 3 );
+* // returns [ 2, 4, 6 ]
+*
+* var count = thisArg.count;
+* // returns 3
+*/
+declare function mapArguments<
+	T extends ( ...args: Array<any> ) => any,
+	C extends ( this: ThisParameterType<T>, value: Parameters<T>[number], index: number ) => any,
+	ThisArg
+>(
+	fcn: T,
+	clbk: C,
+	thisArg: ThisArg
+): ( this: ThisArg, ...args: Parameters<T> ) => ReturnType<T>;
 
 
 // EXPORTS //

diff --git a/lib/node_modules/@stdlib/utils/map-arguments/docs/types/test.ts b/lib/node_modules/@stdlib/utils/map-arguments/docs/types/test.ts
@@ -18,23 +18,37 @@
 
 import mapArguments = require( './index' );
 
-/**
-* Callback function.
-*
-* @param v - argument
-* @returns result
-*/
+// FUNCTIONS //
+
 function clbk<T>( v: T ): T {
 	return v;
 }
 
+function stringify( n: number ): string {
+	return n.toString();
+}
+
+function sum( ...numbers: Array<number> ): number {
+	return numbers.reduce( ( a, b ) => a + b, 0 );
+}
+
+function greet( this: { name: string }, greeting: string ): string {
+	return `${greeting}, ${this.name}!`; // eslint-disable-line no-invalid-this
+}
+
 
 // TESTS //
 
 // The function returns a function...
 {
-	mapArguments<number>( ( x, y, z ): Array<number> => [ x, y, z ], clbk ); // $ExpectType (...args: number[]) => number[]
-	mapArguments<string>( ( x, y, z ): Array<string> => [ x, y, z ], clbk, {} ); // $ExpectType (...args: string[]) => string[]
+	mapArguments( ( x: number, y: number, z: number ): Array<number> => [ x, y, z ], clbk ); // $ExpectType (x: number, y: number, z: number) => number[]
+	mapArguments( ( x: string, y: string, z: string ): Array<string> => [ x, y, z ], clbk, {} ); // $ExpectType (this: {}, x: string, y: string, z: string) => string[]
+	mapArguments( ( x: number, y: number ): number => x + y, clbk ); // $ExpectType (x: number, y: number) => number
+
+	mapArguments( stringify, ( x: number ) => x * 2 ); // $ExpectType (n: number) => string
+	mapArguments( sum, ( x: number ) => x * 2 ); // $ExpectType (...args: number[]) => number
+
+	mapArguments( greet, ( s: string ) => s.toUpperCase(), { 'name': 'World' } ); // $ExpectType (this: { name: string; }, greeting: string) => string
 }
 
 // The compiler throws an error if the function is provided a first argument other than a function...
@@ -56,24 +70,24 @@ function clbk<T>( v: T ): T {
 
 // The compiler throws an error if the function is provided a second argument other than a function...
 {
-	mapArguments<string>( ( x, y, z ): Array<string> => [ x, y, z ], '5' ); // $ExpectError
-	mapArguments<string>( ( x, y, z ): Array<string> => [ x, y, z ], true ); // $ExpectError
-	mapArguments<string>( ( x, y, z ): Array<string> => [ x, y, z ], false ); // $ExpectError
-	mapArguments<string>( ( x, y, z ): Array<string> => [ x, y, z ], 123 ); // $ExpectError
-	mapArguments<string>( ( x, y, z ): Array<string> => [ x, y, z ], null ); // $ExpectError
-	mapArguments<string>( ( x, y, z ): Array<string> => [ x, y, z ], {} ); // $ExpectError
-	mapArguments<string>( ( x, y, z ): Array<string> => [ x, y, z ], [] ); // $ExpectError
-
-	mapArguments<string>( ( x, y, z ): Array<string> => [ x, y, z ], '5', {} ); // $ExpectError
-	mapArguments<string>( ( x, y, z ): Array<string> => [ x, y, z ], true, {} ); // $ExpectError
-	mapArguments<string>( ( x, y, z ): Array<string> => [ x, y, z ], false, {} ); // $ExpectError
-	mapArguments<string>( ( x, y, z ): Array<string> => [ x, y, z ], 123, {} ); // $ExpectError
-	mapArguments<string>( ( x, y, z ): Array<string> => [ x, y, z ], null, {} ); // $ExpectError
-	mapArguments<string>( ( x, y, z ): Array<string> => [ x, y, z ], {}, {} ); // $ExpectError
-	mapArguments<string>( ( x, y, z ): Array<string> => [ x, y, z ], [], {} ); // $ExpectError
+	mapArguments( ( x, y, z ): Array<string> => [ x, y, z ], '5' ); // $ExpectError
+	mapArguments( ( x, y, z ): Array<string> => [ x, y, z ], true ); // $ExpectError
+	mapArguments( ( x, y, z ): Array<string> => [ x, y, z ], false ); // $ExpectError
+	mapArguments( ( x, y, z ): Array<string> => [ x, y, z ], 123 ); // $ExpectError
+	mapArguments( ( x, y, z ): Array<string> => [ x, y, z ], null ); // $ExpectError
+	mapArguments( ( x, y, z ): Array<string> => [ x, y, z ], {} ); // $ExpectError
+	mapArguments( ( x, y, z ): Array<string> => [ x, y, z ], [] ); // $ExpectError
+
+	mapArguments( ( x, y, z ): Array<string> => [ x, y, z ], '5', {} ); // $ExpectError
+	mapArguments( ( x, y, z ): Array<string> => [ x, y, z ], true, {} ); // $ExpectError
+	mapArguments( ( x, y, z ): Array<string> => [ x, y, z ], false, {} ); // $ExpectError
+	mapArguments( ( x, y, z ): Array<string> => [ x, y, z ], 123, {} ); // $ExpectError
+	mapArguments( ( x, y, z ): Array<string> => [ x, y, z ], null, {} ); // $ExpectError
+	mapArguments( ( x, y, z ): Array<string> => [ x, y, z ], {}, {} ); // $ExpectError
+	mapArguments( ( x, y, z ): Array<string> => [ x, y, z ], [], {} ); // $ExpectError
 }
 
 // The compiler throws an error if the function is provided more than three arguments...
 {
-	mapArguments<number>( ( x, y ): number => x + y, clbk, {}, 4 ); // $ExpectError
+	mapArguments( ( x, y ): number => x + y, clbk, {}, 4 ); // $ExpectError
 }