Rename js snippets

snippets/js/s/cross-product-of-arrays.md

@@ -0,0 +1,21 @@
+---
+title: Cross product of arrays
+type: snippet
+language: javascript
+tags: [math,array]
+cover: cup-of-orange
+dateModified: 2020-10-22T20:24:44+03:00
+---
+
+Creates a new array out of the two supplied by creating each possible pair from the arrays.
+
+- Use `Array.prototype.reduce()`, `Array.prototype.map()` and `Array.prototype.concat()` to produce every possible pair from the elements of the two arrays.
+
+```js
+const xProd = (a, b) =>
+  a.reduce((acc, x) => acc.concat(b.map(y => [x, y])), []);
+```
+
+```js
+xProd([1, 2], ['a', 'b']); // [[1, 'a'], [1, 'b'], [2, 'a'], [2, 'b']]
+```