ramda/src/findLast.js

A practical functional library for JavaScript programmers.

var _curry2 = /*#__PURE__*/require("./internal/_curry2.js");
var _dispatchable = /*#__PURE__*/require("./internal/_dispatchable.js");
var _xfindLast = /*#__PURE__*/require("./internal/_xfindLast.js");
/**
 * Returns the last element of the list which matches the predicate, or
 * `undefined` if no element matches.
 *
 * Acts as a transducer if a transformer is given in list position.
 *
 * @func
 * @memberOf R
 * @since v0.1.1
 * @category List
 * @sig (a -> Boolean) -> [a] -> a | undefined
 * @param {Function} fn The predicate function used to determine if the element is the
 * desired one.
 * @param {Array} list The array to consider.
 * @return {Object} The element found, or `undefined`.
 * @see R.transduce
 * @example
 *
 *      const xs = [{a: 1, b: 0}, {a:1, b: 1}];
 *      R.findLast(R.propEq(1, 'a'))(xs); //=> {a: 1, b: 1}
 *      R.findLast(R.propEq(4, 'a'))(xs); //=> undefined
 */
var findLast = /*#__PURE__*/_curry2( /*#__PURE__*/_dispatchable([], _xfindLast, function findLast(fn, list) {
  var idx = list.length - 1;
  while (idx >= 0) {
    if (fn(list[idx])) {
      return list[idx];
    }
    idx -= 1;
  }
}));
module.exports = findLast;