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x/ramda/reduceRight.js

:ram: Practical functional Javascript
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import _curry3 from './internal/_curry3';

/** * Returns a single item by iterating through the list, successively calling * the iterator function and passing it an accumulator value and the current * value from the array, and then passing the result to the next call. * * Similar to [`reduce`](#reduce), except moves through the input list from the * right to the left. * * The iterator function receives two values: *(value, acc)*, while the arguments' * order of `reduce`'s iterator function is *(acc, value)*. * * Note: `R.reduceRight` does not skip deleted or unassigned indices (sparse * arrays), unlike the native `Array.prototype.reduceRight` method. For more details * on this behavior, see: * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/reduceRight#Description * * @func * @memberOf R * @since v0.1.0 * @category List * @sig ((a, b) -> b) -> b -> [a] -> b * @param {Function} fn The iterator function. Receives two values, the current element from the array * and the accumulator. * @param {*} acc The accumulator value. * @param {Array} list The list to iterate over. * @return {*} The final, accumulated value. * @see R.reduce, R.addIndex * @example * * R.reduceRight(R.subtract, 0, [1, 2, 3, 4]) // => (1 - (2 - (3 - (4 - 0)))) = -2 * // - -2 * // / \ / \ * // 1 - 1 3 * // / \ / \ * // 2 - ==> 2 -1 * // / \ / \ * // 3 - 3 4 * // / \ / \ * // 4 0 4 0 * * @symb R.reduceRight(f, a, [b, c, d]) = f(b, f(c, f(d, a))) */var reduceRight = _curry3(function reduceRight(fn, acc, list) { var idx = list.length - 1; while (idx >= 0) { acc = fn(list[idx], acc); idx -= 1; } return acc;});export default reduceRight;