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