intersectionWith.js•1.96 kB
var _containsWith = require('./internal/_containsWith');
var _curry3 = require('./internal/_curry3');
var uniqWith = require('./uniqWith');
/**
* Combines two lists into a set (i.e. no duplicates) composed of those
* elements common to both lists. Duplication is determined according to the
* value returned by applying the supplied predicate to two list elements.
*
* @func
* @memberOf R
* @since v0.1.0
* @category Relation
* @sig (a -> a -> Boolean) -> [*] -> [*] -> [*]
* @param {Function} pred A predicate function that determines whether
* the two supplied elements are equal.
* @param {Array} list1 One list of items to compare
* @param {Array} list2 A second list of items to compare
* @return {Array} A new list containing those elements common to both lists.
* @see R.intersection
* @example
*
* var buffaloSpringfield = [
* {id: 824, name: 'Richie Furay'},
* {id: 956, name: 'Dewey Martin'},
* {id: 313, name: 'Bruce Palmer'},
* {id: 456, name: 'Stephen Stills'},
* {id: 177, name: 'Neil Young'}
* ];
* var csny = [
* {id: 204, name: 'David Crosby'},
* {id: 456, name: 'Stephen Stills'},
* {id: 539, name: 'Graham Nash'},
* {id: 177, name: 'Neil Young'}
* ];
*
* R.intersectionWith(R.eqBy(R.prop('id')), buffaloSpringfield, csny);
* //=> [{id: 456, name: 'Stephen Stills'}, {id: 177, name: 'Neil Young'}]
*/
module.exports = _curry3(function intersectionWith(pred, list1, list2) {
var lookupList, filteredList;
if (list1.length > list2.length) {
lookupList = list1;
filteredList = list2;
} else {
lookupList = list2;
filteredList = list1;
}
var results = [];
var idx = 0;
while (idx < filteredList.length) {
if (_containsWith(pred, filteredList[idx], lookupList)) {
results[results.length] = filteredList[idx];
}
idx += 1;
}
return uniqWith(pred, results);
});