Add Typescript definition

lib/node_modules/@stdlib/utils/reduce/docs/types/index.d.ts

@@ -0,0 +1,116 @@
+/*
+* @license Apache-2.0
+*
+* Copyright (c) 2019 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+// TypeScript Version: 2.0
+
+/// <reference types="@stdlib/types"/>
+
+import { Collection } from '@stdlib/types/object';
+
+/**
+* Function applied against an accumulator.
+*
+* @returns accumulator value
+*/
+type Nullary = () => void;
+
+/**
+* Function applied against an accumulator.
+*
+* @param accumulator - accumulated value
+* @returns accumulator value
+*/
+type Unary = ( accumulator: any ) => any;
+
+/**
+* Function applied against an accumulator.
+*
+* @param accumulator - accumulated value
+* @param value - collection value
+* @returns accumulator value
+*/
+type Binary = ( accumulator: any, value: any ) => any;
+
+/**
+* Function applied against an accumulator.
+*
+* @param accumulator - accumulated value
+* @param value - collection value
+* @param index - collection index
+* @returns accumulator value
+*/
+type Tertiary = ( accumulator: any, value: any, index: number ) => any;
+
+/**
+* Function applied against an accumulator.
+*
+* @param accumulator - accumulated value
+* @param value - collection value
+* @param index - collection index
+* @param collection - the input collection
+* @returns accumulator value
+*/
+type Quaternary = ( accumulator: any, value: any, index: number, collection: Collection ) => any; // tslint-disable-line max-line-length
+
+/**
+* Function applied against an accumulator.
+*
+* @param accumulator - accumulated value
+* @param value - collection value
+* @param index - collection index
+* @param collection - the input collection
+* @returns accumulator value
+*/
+type Reducer = Nullary | Unary | Binary | Tertiary | Quaternary;
+
+/**
+* Applies a function against an accumulator and each element in a collection and returns the accumulated result.
+*
+* ## Notes
+*
+* -   When invoked, the reduction function is provided four arguments:
+*
+*     -   `accumulator`: accumulated value
+*     -   `value`: collection value
+*     -   `index`: collection index
+*     -   `collection`: the input collection
+*
+* -   If provided an empty collection, the function returns the initial value.
+*
+* @param collection - input collection
+* @param initial - initial value
+* @param reducer - reduction function
+* @param thisArg - reduction function execution context
+* @returns accumulated result
+*
+* @example
+* function sum( acc, value ) {
+*     return acc + value;
+* }
+*
+* var arr = [ 1, 2, 3, 4 ];
+*
+* var s = reduce( arr, 0, sum );
+* // returns 10
+*/
+declare function reduce( collection: Collection, initial: any, reducer: Reducer, thisArg?: any ): any; // tslint-disable-line max-line-length
+
+
+// EXPORTS //
+
+export = reduce;

lib/node_modules/@stdlib/utils/reduce/docs/types/test.ts

@@ -0,0 +1,59 @@
+/*
+* @license Apache-2.0
+*
+* Copyright (c) 2019 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+import reduce = require( './index' );
+
+const sum = ( acc: number, value: number ): number => {
+	return acc + value;
+};
+
+
+// TESTS //
+
+// The function returns the accumulated value...
+{
+	reduce( [ 0, 1, 1, NaN, 2 ], 0, sum ); // $ExpectType any
+	reduce( [ -1, 1, 2 ], 100, sum ); // $ExpectType any
+	reduce( [ -1, 1, 2 ], 0, sum, {} ); // $ExpectType any
+}
+
+// The compiler throws an error if the function is provided a first argument which is not a collection...
+{
+	reduce( 2, 0, sum ); // $ExpectError
+	reduce( false, 0, sum ); // $ExpectError
+	reduce( true, 0, sum ); // $ExpectError
+	reduce( {}, 0, sum ); // $ExpectError
+}
+
+// The compiler throws an error if the function is provided a third argument which is not a function...
+{
+	reduce( [ 0, 1, 1, NaN, 2 ], 0, 2 ); // $ExpectError
+	reduce( [ 0, 1, 1, NaN, 2 ], 0, false ); // $ExpectError
+	reduce( [ 0, 1, 1, NaN, 2 ], 0, true ); // $ExpectError
+	reduce( [ 0, 1, 1, NaN, 2 ], 0, 'abc' ); // $ExpectError
+	reduce( [ 0, 1, 1, NaN, 2 ], 0, {} ); // $ExpectError
+	reduce( [ 0, 1, 1, NaN, 2 ], 0, [] ); // $ExpectError
+}
+
+// The compiler throws an error if the function is provided an invalid number of arguments...
+{
+	reduce(); // $ExpectError
+	reduce( [ 1, 2, 3 ] ); // $ExpectError
+	reduce( [ 1, 2, 3 ], 0 ); // $ExpectError
+	reduce( [ 1, 2, 3 ], 0, sum, {}, 3 ); // $ExpectError
+}

lib/node_modules/@stdlib/utils/reduce/package.json

@@ -21,6 +21,7 @@
     "lib": "./lib",
     "test": "./test"
   },
+  "types": "./docs/types",
   "scripts": {},
   "homepage": "https://github.com/stdlib-js/stdlib",
   "repository": {