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@stdlib/utils

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Standard utilities.

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/* * @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, V> { /** * The maximum number of pending invocations at any one time. */ limit?: number; /** * Boolean indicating whether to sequentially invoke the `predicate` function for each `collection` element. If `true`, the function sets `options.limit=1`. */ series?: boolean; /** * Execution context. */ thisArg?: ThisParameterType<Predicate<T, V>>; } /** * 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 result - test result */ type Binary = ( error: Error | null, result: boolean ) => void; /** * Callback function. * * @param error - encountered error or null * @param result - test result */ type Callback = Nullary | Unary | Binary; /** * Checks whether an element in a collection passes a test. * * @param value - collection value * @param next - callback which should be called once the predicate function has finished processing a collection value */ type BinaryPredicate<T, V> = ( this: V, value: T, next: Callback ) => void; /** * Checks whether an element in a collection passes a test. * * @param value - collection value * @param index - collection index * @param next - callback which should be called once the `predicate` function has finished processing a collection `value` */ type TernaryPredicate<T, V> = ( this: V, value: T, index: number, next: Callback ) => void; /** * Checks whether an element in a collection passes a test. * * @param value - collection value * @param index - collection index * @param collection - input collection * @param next - callback which should be called once the `predicate` function has finished processing a collection `value` */ type QuaternaryPredicate<T, V> = ( this: V, value: T, index: number, collection: Collection<T>, next: Callback ) => void; /** * Checks whether an element in a collection passes a test. * * @param value - collection value * @param index - collection index * @param collection - input collection * @param next - callback which should be called once the `predicate` function has finished processing a collection `value` */ type Predicate<T, V> = BinaryPredicate<T, V> | TernaryPredicate<T, V> | QuaternaryPredicate<T, V>; /** * Tests whether at least `n` elements in a collection pass a test implemented by a predicate function. * * @param collection - input collection * @param n - number of elements * @param done - function to invoke upon completion */ type FactoryFunction<T> = ( collection: Collection<T>, n: number, done: Callback ) => void; /** * Interface for `someByRightAsync`. */ interface SomeByRightAsync { /** * Tests whether a collection contains at least `n` elements which pass a test implemented by a predicate function, iterating from right to left. * * ## Notes * * - If a predicate 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 n - number of elements * @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: false) * @param predicate - predicate function to invoke for each element in a collection * @param done - function to invoke upon completion * @throws second argument must be a positive integer * @throws must provide valid options * * @example * var readFile = require( '@stdlib/fs/read-file' ); * * function done( error, bool ) { * if ( error ) { * throw error; * } * if ( bool ) { * console.log( 'Successfully read some files.' ); * } else { * console.log( 'Unable to read some files.' ); * } * } * * function predicate( file, next ) { * var opts = { * 'encoding': 'utf8' * }; * readFile( file, opts, onFile ); * * function onFile( error ) { * if ( error ) { * return next( null, false ); * } * next( null, true ); * } * } * * var files = [ * './beep.js', * './boop.js' * ]; * * someByRightAsync( files, 2, predicate, done ); */ <T = unknown, V = unknown>( collection: Collection<T>, n: number, options: Options<T, V>, predicate: Predicate<T, V>, done: Callback ): void; /** * Tests whether a collection contains at least `n` elements which pass a test implemented by a predicate function, iterating from right to left. * * ## Notes * * - If a predicate 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 n - number of elements * @param predicate - predicate function to invoke for each element in a collection * @param done - function to invoke upon completion * @throws second argument must be a positive integer * @throws must provide valid options * * @example * var readFile = require( '@stdlib/fs/read-file' ); * * function done( error, bool ) { * if ( error ) { * throw error; * } * if ( bool ) { * console.log( 'Successfully read some files.' ); * } else { * console.log( 'Unable to read some files.' ); * } * } * * function predicate( file, next ) { * var opts = { * 'encoding': 'utf8' * }; * readFile( file, opts, onFile ); * * function onFile( error ) { * if ( error ) { * return next( null, false ); * } * next( null, true ); * } * } * * var files = [ * './beep.js', * './boop.js' * ]; * * someByRightAsync( files, 2, predicate, done ); */ <T = unknown, V = unknown>( collection: Collection<T>, n: number, predicate: Predicate<T, V>, done: Callback ): void; /** * Returns a function for testing whether a collection contains at least `n` elements which pass a test implemented by a predicate function, iterating from right to left. * * ## Notes * * - If a predicate 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: false) * @param predicate - predicate function to invoke for each element in a collection * @throws must provide valid options * @returns function which invokes the predicate function once for each element in a collection * * @example * var readFile = require( '@stdlib/fs/read-file' ); * * function predicate( file, next ) { * var opts = { * 'encoding': 'utf8' * }; * readFile( file, opts, onFile ); * * function onFile( error ) { * if ( error ) { * return next( null, false ); * } * next( null, true ); * } * } * * var opts = { * 'series': true * }; * * // Create a `someByRightAsync` function which invokes the predicate function for each collection element sequentially: * var someByRightAsync = factory( opts, predicate ); * * // Create a collection over which to iterate: * var files = [ * './beep.js', * './boop.js' * ]; * * // Define a callback which handles results: * function done( error, bool ) { * if ( error ) { * throw error; * } * if ( bool ) { * console.log( 'Successfully read some files.' ); * } else { * console.log( 'Unable to read some files.' ); * } * } * * // Try to read each element in `files`: * someByRightAsync( files, 2, done ); */ factory<T = unknown, V = unknown>( options: Options<T, V>, predicate: Predicate<T, V> ): FactoryFunction<T>; /** * Returns a function for testing whether a collection contains at least `n` elements which pass a test implemented by a predicate function, iterating from right to left. * * ## Notes * * - If a predicate 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 predicate - predicate function to invoke for each element in a collection * @throws must provide valid options * @returns function which invokes the predicate function once for each element in a collection * * @example * var readFile = require( '@stdlib/fs/read-file' ); * * function predicate( file, next ) { * var opts = { * 'encoding': 'utf8' * }; * readFile( file, opts, onFile ); * * function onFile( error ) { * if ( error ) { * return next( null, false ); * } * next( null, true ); * } * } * * var opts = { * 'series': true * }; * * // Create a `someByRightAsync` function which invokes the predicate function for each collection element sequentially: * var someByRightAsync = factory( opts, predicate ); * * // Create a collection over which to iterate: * var files = [ * './beep.js', * './boop.js' * ]; * * // Define a callback which handles results: * function done( error, bool ) { * if ( error ) { * throw error; * } * if ( bool ) { * console.log( 'Successfully read some files.' ); * } else { * console.log( 'Unable to read some files.' ); * } * } * * // Try to read each element in `files`: * someByRightAsync( files, 2, done ); */ factory<T = unknown, V = unknown>( predicate: Predicate<T, V> ): FactoryFunction<T>; } /** * Tests whether a collection contains at least `n` elements which pass a test implemented by a predicate function, iterating from right to left. * * ## Notes * * - If a predicate 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 n - number of elements * @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: false) * @param predicate - predicate function to invoke for each element in a collection * @param done - function to invoke upon completion * @throws second argument must be a positive integer * @throws must provide valid options * * @example * var readFile = require( '@stdlib/fs/read-file' ); * * function done( error, bool ) { * if ( error ) { * throw error; * } * if ( bool ) { * console.log( 'Successfully read some files.' ); * } else { * console.log( 'Unable to read some files.' ); * } * } * * function predicate( file, next ) { * var opts = { * 'encoding': 'utf8' * }; * readFile( file, opts, onFile ); * * function onFile( error ) { * if ( error ) { * return next( null, false ); * } * next( null, true ); * } * } * * var files = [ * './beep.js', * './boop.js' * ]; * * someByRightAsync( files, 2, predicate, done ); */ declare var someByRightAsync: SomeByRightAsync; // EXPORTS // export = someByRightAsync;