jiapengyu
39 lines
1.3 KiB
JavaScript
39 lines
1.3 KiB
JavaScript
import _concat from './internal/_concat';
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import _curry3 from './internal/_curry3';
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/**
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* Applies a function to the value at the given index of an array, returning a
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* new copy of the array with the element at the given index replaced with the
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* result of the function application.
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*
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* @func
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* @memberOf R
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* @since v0.14.0
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* @category List
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* @sig (a -> a) -> Number -> [a] -> [a]
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* @param {Function} fn The function to apply.
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* @param {Number} idx The index.
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* @param {Array|Arguments} list An array-like object whose value
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* at the supplied index will be replaced.
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* @return {Array} A copy of the supplied array-like object with
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* the element at index `idx` replaced with the value
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* returned by applying `fn` to the existing element.
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* @see R.update
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* @example
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*
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* R.adjust(R.add(10), 1, [1, 2, 3]); //=> [1, 12, 3]
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* R.adjust(R.add(10))(1)([1, 2, 3]); //=> [1, 12, 3]
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* @symb R.adjust(f, -1, [a, b]) = [a, f(b)]
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* @symb R.adjust(f, 0, [a, b]) = [f(a), b]
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*/
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var adjust = /*#__PURE__*/_curry3(function adjust(fn, idx, list) {
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if (idx >= list.length || idx < -list.length) {
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return list;
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}
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var start = idx < 0 ? list.length : 0;
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var _idx = start + idx;
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var _list = _concat(list);
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_list[_idx] = fn(list[_idx]);
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return _list;
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});
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export default adjust; |