40 lines
No EOL
1.3 KiB
JavaScript
40 lines
No EOL
1.3 KiB
JavaScript
import _curry3 from "./internal/_curry3.js";
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import _dispatchable from "./internal/_dispatchable.js";
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import _xscan from "./internal/_xscan.js";
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/**
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* Scan is similar to [`reduce`](#reduce), but returns a list of successively
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* reduced values from the left.
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*
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* Acts as a transducer if a transformer is given in list position.
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*
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* @func
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* @memberOf R
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* @since v0.10.0
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* @category List
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* @sig ((a, b) -> a) -> a -> [b] -> [a]
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* @param {Function} fn The iterator function. Receives two values, the accumulator and the
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* current element from the array
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* @param {*} acc The accumulator value.
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* @param {Array} list The list to iterate over.
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* @return {Array} A list of all intermediately reduced values.
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* @see R.reduce, R.mapAccum
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* @example
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*
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* const numbers = [1, 2, 3, 4];
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* const factorials = R.scan(R.multiply, 1, numbers); //=> [1, 1, 2, 6, 24]
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* @symb R.scan(f, a, [b, c]) = [a, f(a, b), f(f(a, b), c)]
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*/
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var scan = /*#__PURE__*/_curry3( /*#__PURE__*/_dispatchable([], _xscan, function scan(fn, acc, list) {
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var idx = 0;
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var len = list.length;
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var result = Array(len + 1);
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result[0] = acc;
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while (idx < len) {
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acc = fn(acc, list[idx]);
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result[idx + 1] = acc;
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idx += 1;
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}
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return result;
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}));
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export default scan; |