106 lines
2.5 KiB
JavaScript
106 lines
2.5 KiB
JavaScript
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/**
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* @license Apache-2.0
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*
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* Copyright (c) 2018 The Stdlib Authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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'use strict';
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// MODULES //
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var isFunction = require( '@stdlib/assert/is-function' );
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var isPositiveInteger = require( '@stdlib/assert/is-positive-integer' ).isPrimitive;
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// MAIN //
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/**
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* Transforms a function into a sequence of functions each accepting a single argument.
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*
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* @param {Function} fcn - function to curry
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* @param {PositiveInteger} [arity=fcn.length] - number of parameters
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* @param {*} [thisArg] - evaluation context
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* @throws {TypeError} first argument must be a function
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* @throws {TypeError} `arity` argument must be a positive integer
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* @returns {Function} curry function
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*
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* @example
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* function add( x, y ) {
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* return x + y;
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* }
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*
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* var f = curry( add );
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*
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* var sum = f( 2 )( 3 );
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* // returns 5
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*/
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function curry( fcn, arity, thisArg ) {
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var context;
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var len;
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if ( !isFunction( fcn ) ) {
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throw new TypeError( 'invalid argument. First argument must be a function. Value: `' + fcn + '`.' );
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}
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if ( arguments.length < 2 ) {
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len = fcn.length;
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}
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else if ( arguments.length > 2 ) {
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len = arity;
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context = thisArg;
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if ( !isPositiveInteger( len ) ) {
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throw new TypeError( 'invalid argument. Arity argument must be positive integer. Value: `' + len + '`.' );
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}
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}
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else if ( isPositiveInteger( arity ) ) {
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len = arity;
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}
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else {
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len = fcn.length;
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context = arity;
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}
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return createCurried( [] );
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/**
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* Returns a curry function.
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*
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* @private
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* @param {Array} args - arguments
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* @returns {Function} curry function
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*/
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function createCurried( args ) {
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return curried;
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/**
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* Curry function.
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*
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* @private
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* @param {*} v - curried function parameter
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* @returns {(Function|*)} partially applied curry function or curried function result
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*/
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function curried( v ) {
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var cargs = args.slice();
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cargs.push( v );
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if ( cargs.length < len ) {
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return createCurried( cargs );
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}
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return fcn.apply( context, cargs );
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}
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}
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}
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// EXPORTS //
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module.exports = curry;
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