jiapengyu
37 lines
1.2 KiB
JavaScript
37 lines
1.2 KiB
JavaScript
import _curry2 from './internal/_curry2';
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import _dispatchable from './internal/_dispatchable';
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import _makeFlat from './internal/_makeFlat';
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import _xchain from './internal/_xchain';
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import map from './map';
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/**
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* `chain` maps a function over a list and concatenates the results. `chain`
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* is also known as `flatMap` in some libraries
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*
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* Dispatches to the `chain` method of the second argument, if present,
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* according to the [FantasyLand Chain spec](https://github.com/fantasyland/fantasy-land#chain).
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*
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* @func
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* @memberOf R
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* @since v0.3.0
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* @category List
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* @sig Chain m => (a -> m b) -> m a -> m b
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* @param {Function} fn The function to map with
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* @param {Array} list The list to map over
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* @return {Array} The result of flat-mapping `list` with `fn`
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* @example
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*
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* var duplicate = n => [n, n];
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* R.chain(duplicate, [1, 2, 3]); //=> [1, 1, 2, 2, 3, 3]
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*
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* R.chain(R.append, R.head)([1, 2, 3]); //=> [1, 2, 3, 1]
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*/
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var chain = /*#__PURE__*/_curry2( /*#__PURE__*/_dispatchable(['fantasy-land/chain', 'chain'], _xchain, function chain(fn, monad) {
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if (typeof monad === 'function') {
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return function (x) {
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return fn(monad(x))(x);
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};
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}
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return _makeFlat(false)(map(fn, monad));
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}));
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export default chain; |