46 lines
1.6 KiB
JavaScript
46 lines
1.6 KiB
JavaScript
import _curryN from "./internal/_curryN.js";
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import _xReduce from "./internal/_xReduce.js";
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import _xwrap from "./internal/_xwrap.js";
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import _reduced from "./internal/_reduced.js";
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/**
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* Like [`reduce`](#reduce), `reduceWhile` returns a single item by iterating
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* through the list, successively calling the iterator function. `reduceWhile`
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* also takes a predicate that is evaluated before each step. If the predicate
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* returns `false`, it "short-circuits" the iteration and returns the current
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* value of the accumulator. `reduceWhile` may alternatively be short-circuited
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* via [`reduced`](#reduced).
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*
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* @func
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* @memberOf R
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* @since v0.22.0
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* @category List
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* @sig ((a, b) -> Boolean) -> ((a, b) -> a) -> a -> [b] -> a
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* @param {Function} pred The predicate. It is passed the accumulator and the
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* current element.
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* @param {Function} fn The iterator function. Receives two values, the
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* accumulator and the current element.
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* @param {*} a The accumulator value.
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* @param {Array} list The list to iterate over.
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* @return {*} The final, accumulated value.
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* @see R.reduce, R.reduced
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* @example
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*
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* const isOdd = (acc, x) => x % 2 !== 0;
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* const xs = [1, 3, 5, 60, 777, 800];
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* R.reduceWhile(isOdd, R.add, 0, xs); //=> 9
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*
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* const ys = [2, 4, 6]
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* R.reduceWhile(isOdd, R.add, 111, ys); //=> 111
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*/
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var reduceWhile =
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/*#__PURE__*/
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_curryN(4, [], function _reduceWhile(pred, fn, a, list) {
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var xf = _xwrap(function (acc, x) {
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return pred(acc, x) ? fn(acc, x) : _reduced(acc);
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});
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return _xReduce(xf, a, list);
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});
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export default reduceWhile; |