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x/ramda/source/groupWith.js

:ram: Practical functional Javascript
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import _curry2 from './internal/_curry2.js';
/** * Takes a list and returns a list of lists where each sublist's elements are * all satisfied pairwise comparison according to the provided function. * Only adjacent elements are passed to the comparison function. * * @func * @memberOf R * @since v0.21.0 * @category List * @sig ((a, a) → Boolean) → [a] → [[a]] * @param {Function} fn Function for determining whether two given (adjacent) * elements should be in the same group * @param {Array} list The array to group. Also accepts a string, which will be * treated as a list of characters. * @return {List} A list that contains sublists of elements, * whose concatenations are equal to the original list. * @example * * R.groupWith(R.equals, [0, 1, 1, 2, 3, 5, 8, 13, 21]) * //=> [[0], [1, 1], [2], [3], [5], [8], [13], [21]] * * R.groupWith((a, b) => a + 1 === b, [0, 1, 1, 2, 3, 5, 8, 13, 21]) * //=> [[0, 1], [1, 2, 3], [5], [8], [13], [21]] * * R.groupWith((a, b) => a % 2 === b % 2, [0, 1, 1, 2, 3, 5, 8, 13, 21]) * //=> [[0], [1, 1], [2], [3, 5], [8], [13, 21]] * * const isVowel = R.test(/^[aeiou]$/i); * R.groupWith(R.eqBy(isVowel), 'aestiou') * //=> ['ae', 'st', 'iou'] */var groupWith = _curry2(function(fn, list) { var res = []; var idx = 0; var len = list.length; while (idx < len) { var nextidx = idx + 1; while (nextidx < len && fn(list[nextidx - 1], list[nextidx])) { nextidx += 1; } res.push(list.slice(idx, nextidx)); idx = nextidx; } return res;});export default groupWith;