@stdlib/utils
Version:
Standard utilities.
411 lines (387 loc) • 14 kB
TypeScript
/*
* @license Apache-2.0
*
* Copyright (c) 2021 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: 4.1
/// <reference types="@stdlib/types"/>
import { Collection } from '@stdlib/types/array';
/**
* Interface defining function options.
*/
interface Options<T, U, V> {
/**
* Execution context.
*/
thisArg?: ThisParameterType<Reducer<T, U, V>>;
/**
* The maximum number of pending invocations at any one time.
*/
limit?: number;
/**
* Boolean indicating whether to sequentially invoke the reducer function for each `collection` element. If `true`, the function sets `options.limit=1`. Default: true.
*/
series?: boolean;
}
/**
* Callback function.
*/
type Nullary = () => void;
/**
* Callback function.
*
* @param error - encountered error or null
*/
type Unary = ( error: Error | null ) => void;
/**
* Callback function.
*
* @param error - encountered error or null
* @param accumulator - accumulated value
*/
type Binary<U> = ( error: Error | null, accumulator: U ) => void;
/**
* Callback function.
*
* @param error - encountered error or null
* @param accumulator - accumulated value
*/
type Callback<U> = Nullary | Unary | Binary<U>;
/**
* Reducer function invoked for each element in a collection.
*
* @param accumulator - accumulated value
* @param value - collection value
* @param next - a callback to be invoked after processing a collection `value`
*/
type TernaryReducer<T, U, V> = ( this: V, accumulator: U, value: T, next: Callback<U> ) => void;
/**
* Reducer function invoked for each element in a collection.
*
* @param accumulator - accumulated value
* @param value - collection value
* @param index - collection index
* @param next - a callback to be invoked after processing a collection `value`
*/
type QuaternaryReducer <T, U, V> = ( this: V, accumulator: U, value: T, index: number, next: Callback<U> ) => void;
/**
* Reducer function invoked for each element in a collection.
*
* @param accumulator - accumulated value
* @param value - collection value
* @param index - collection index
* @param collection - the input collection
* @param next - a callback to be invoked after processing a collection `value`
*/
type QuinaryReducer<T, U, V> = ( this: V, accumulator: U, value: T, index: number, collection: Collection<T>, next: Callback<U> ) => void;
/**
* Reducer function invoked for each element in a collection.
*
* @param accumulator - accumulated value
* @param value - collection value
* @param index - collection index
* @param collection - the input collection
* @param next - a callback to be invoked after processing a collection `value`
*/
type Reducer<T, U, V> = TernaryReducer<T, U, V> | QuaternaryReducer<T, U, V> | QuinaryReducer<T, U, V>;
/**
* Applies a function against an accumulator and each element in a collection and return the accumulated result.
*
* @param collection - input collection
* @param initial - initial value
* @param done - function to invoke upon completion
*/
type FactoryFunction<T, U> = ( collection: Collection<T>, initial: U, done: Callback<U> ) => void;
/**
* Interface for `reduceRightAsync`.
*/
interface ReduceRightAsync {
/**
* Applies a function against an accumulator and each element in a collection and return the accumulated result, iterating from right to left.
*
* ## Notes
*
* - If a provided function calls the provided callback with a truthy error argument, the function suspends execution and immediately calls the `done` callback for subsequent error handling.
* - This function does **not** guarantee that execution is asynchronous. To do so, wrap the `done` callback in a function which either executes at the end of the current stack (e.g., `nextTick`) or during a subsequent turn of the event loop (e.g., `setImmediate`, `setTimeout`).
*
* @param collection - input collection
* @param initial - initial value
* @param options - function options
* @param options.thisArg - execution context
* @param options.limit - maximum number of pending invocations at any one time
* @param options.series - boolean indicating whether to wait for a previous invocation to complete before invoking a provided function for the next element in a collection (default: true)
* @param reducer - function to invoke for each element in a collection
* @param done - function to invoke upon completion
* @throws must provide valid options
*
* @example
* var readFile = require( '@stdlib/fs/read-file' );
*
* function done( error, acc ) {
* if ( error ) {
* throw error;
* }
* console.log( acc.count );
* }
*
* function read( acc, file, next ) {
* var opts = {
* 'encoding': 'utf8'
* };
* readFile( file, opts, onFile );
*
* function onFile( error ) {
* if ( error ) {
* return next( null, acc );
* }
* acc.count += 1;
* next( null, acc );
* }
* }
*
* var files = [
* './beep.js',
* './boop.js'
* ];
* var acc = {
* 'count': 0
* };
* reduceRightAsync( files, acc, {}, read, done );
*/
<T = unknown, U = unknown, V = unknown>( collection: Collection<T>, initial: U, options: Options<T, U, V>, reducer: Reducer<T, U, V>, done: Callback<U> ): void;
/**
* Applies a function against an accumulator and each element in a collection and return the accumulated result, iterating from right to left.
*
* ## Notes
*
* - If a provided function calls the provided callback with a truthy error argument, the function suspends execution and immediately calls the `done` callback for subsequent error handling.
* - This function does **not** guarantee that execution is asynchronous. To do so, wrap the `done` callback in a function which either executes at the end of the current stack (e.g., `nextTick`) or during a subsequent turn of the event loop (e.g., `setImmediate`, `setTimeout`).
*
* @param collection - input collection
* @param initial - initial value
* @param options - function options
* @param options.thisArg - execution context
* @param options.limit - maximum number of pending invocations at any one time
* @param options.series - boolean indicating whether to wait for a previous invocation to complete before invoking a provided function for the next element in a collection (default: true)
* @param reducer - function to invoke for each element in a collection
* @param done - function to invoke upon completion
* @throws must provide valid options
*
* @example
* var readFile = require( '@stdlib/fs/read-file' );
*
* function done( error, acc ) {
* if ( error ) {
* throw error;
* }
* console.log( acc.count );
* }
*
* function read( acc, file, next ) {
* var opts = {
* 'encoding': 'utf8'
* };
* readFile( file, opts, onFile );
*
* function onFile( error ) {
* if ( error ) {
* return next( null, acc );
* }
* acc.count += 1;
* next( null, acc );
* }
* }
*
* var files = [
* './beep.js',
* './boop.js'
* ];
* var acc = {
* 'count': 0
* };
* reduceRightAsync( files, acc, read, done );
*/
<T = unknown, U = unknown, V = unknown>( collection: Collection<T>, initial: U, reducer: Reducer<T, U, V>, done: Callback<U> ): void;
/**
* Returns a function to apply a function against an accumulator and each element in a collection and return the accumulated result, iterating from right to left.
*
* ## Notes
*
* - If a provided function calls the provided callback with a truthy error argument, the function suspends execution and immediately calls the `done` callback for subsequent error handling.
* - This function does **not** guarantee that execution is asynchronous. To do so, wrap the `done` callback in a function which either executes at the end of the current stack (e.g., `nextTick`) or during a subsequent turn of the event loop (e.g., `setImmediate`, `setTimeout`).
*
* @param options - function options
* @param options.thisArg - execution context
* @param options.limit - maximum number of pending invocations at any one time
* @param options.series - boolean indicating whether to wait for a previous invocation to complete before invoking a provided function for the next element in a collection (default: true)
* @param reducer - function to invoke for each element in a collection
* @throws must provide valid options
* @returns function which invokes the provided function once for each element in a collection
*
* @example
* var readFile = require( '@stdlib/fs/read-file' );
*
* function read( acc, file, next ) {
* var opts = {
* 'encoding': 'utf8'
* };
* readFile( file, opts, onFile );
*
* function onFile( error, data ) {
* if ( error ) {
* return next( null, acc );
* }
* acc.count += 1;
* next( null, acc );
* }
* }
*
* var opts = {
* 'series': false
* };
*
* // Create a `reduceRightAsync` function which invokes `read` for each collection element concurrently:
* var reduceRightAsync = factory( opts, read );
*
* // Create a collection over which to iterate:
* var files = [
* './beep.js',
* './boop.js'
* ];
*
* // Define a callback which handles errors:
* function done( error, acc ) {
* if ( error ) {
* throw error;
* }
* console.log( acc.count );
* }
*
* // Run `read` for each element in `files`:
* var acc = {
* 'count': 0
* };
* reduceRightAsync( files, acc, done );
*/
factory<T = unknown, U = unknown, V = unknown>( options: Options<T, U, V>, reducer: Reducer<T, U, V> ): FactoryFunction<T, U>;
/**
* Returns a function to apply a function against an accumulator and each element in a collection and return the accumulated result, iterating from right to left.
*
* ## Notes
*
* - If a provided function calls the provided callback with a truthy error argument, the function suspends execution and immediately calls the `done` callback for subsequent error handling.
* - This function does **not** guarantee that execution is asynchronous. To do so, wrap the `done` callback in a function which either executes at the end of the current stack (e.g., `nextTick`) or during a subsequent turn of the event loop (e.g., `setImmediate`, `setTimeout`).
*
* @param reducer - function to invoke for each element in a collection
* @returns function which invokes the provided function once for each element in a collection
*
* @example
* var readFile = require( '@stdlib/fs/read-file' );
*
* function read( acc, file, next ) {
* var opts = {
* 'encoding': 'utf8'
* };
* readFile( file, opts, onFile );
*
* function onFile( error, data ) {
* if ( error ) {
* return next( null, acc );
* }
* acc.count += 1;
* next( null, acc );
* }
* }
*
* // Create a `reduceRightAsync` function which invokes `read` for each collection element concurrently:
* var reduceRightAsync = factory( read );
*
* // Create a collection over which to iterate:
* var files = [
* './beep.js',
* './boop.js'
* ];
*
* // Define a callback which handles errors:
* function done( error, acc ) {
* if ( error ) {
* throw error;
* }
* console.log( acc.count );
* }
*
* // Run `read` for each element in `files`:
* var acc = {
* 'count': 0
* };
* reduceRightAsync( files, acc, done );
*/
factory<T = unknown, U = unknown, V = unknown>( reducer: Reducer<T, U, V> ): FactoryFunction<T, U>;
}
/**
* Applies a function against an accumulator and each element in a collection and return the accumulated result, iterating from right to left.
*
* ## Notes
*
* - If a provided function calls the provided callback with a truthy error argument, the function suspends execution and immediately calls the `done` callback for subsequent error handling.
* - This function does **not** guarantee that execution is asynchronous. To do so, wrap the `done` callback in a function which either executes at the end of the current stack (e.g., `nextTick`) or during a subsequent turn of the event loop (e.g., `setImmediate`, `setTimeout`).
*
* @param collection - input collection
* @param initial - initial value
* @param options - function options
* @param options.thisArg - execution context
* @param options.limit - maximum number of pending invocations at any one time
* @param options.series - boolean indicating whether to wait for a previous invocation to complete before invoking a provided function for the next element in a collection (default: true)
* @param reducer - function to invoke for each element in a collection
* @param done - function to invoke upon completion
* @throws must provide valid options
*
* @example
* var readFile = require( '@stdlib/fs/read-file' );
*
* function done( error, acc ) {
* if ( error ) {
* throw error;
* }
* console.log( acc.count );
* }
*
* function read( acc, file, next ) {
* var opts = {
* 'encoding': 'utf8'
* };
* readFile( file, opts, onFile );
*
* function onFile( error ) {
* if ( error ) {
* return next( null, acc );
* }
* acc.count += 1;
* next( null, acc );
* }
* }
*
* var files = [
* './beep.js',
* './boop.js'
* ];
* var acc = {
* 'count': 0
* };
* reduceRightAsync( files, acc, read, done );
*/
declare var reduceRightAsync: ReduceRightAsync;
// EXPORTS //
export = reduceRightAsync;