Add intersectionBy, intersectionWith

snippets/intersectionWith.md

@@ -0,0 +1,14 @@
+### intersectionWith
+
+Returns a list of elements that exist in both arrays, using a provided comparator function.
+
+Use `Array.filter()` and `Array.findIndex()` in combination with the provided comparator to determine intersecting values.
+
+```js
+const intersectionWith = (a, b, comp) =>
+  a.filter(x => b.findIndex(y => comp(x, y)) !== -1);
+```
+
+```js
+intersectionWith([1, 1.2, 1.5, 3, 0], [1.9, 3, 0, 3.9], (a, b) => Math.round(a) === Math.round(b)); // [1.5, 3, 0]
+```