Add haveSameContents snippet

snippets/haveSameContents.md

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+---
+title: haveSameContents
+tags: array,intermediate
+---
+
+Returns `true` if two arrays contain the same elements regardless of order, `false` otherwise.
+
+Use a `for...of` loop over a `Set` created from the values of both arrays.
+Use `Array.prototype.filter()` to compare the amount of occurences of each distinct value in both arrays.
+Return `false` if the counts do not match for any element, `true` otherwise.
+
+```js
+const haveSameContents = (a, b) => {
+  for (const v of new Set([...a, ...b]))
+    if (a.filter(e => e === v).length !== b.filter(e => e === v).length)
+      return false;
+  return true;
+}
+```
+
+```js
+haveSameContents([1, 2, 4], [2, 4, 1]); // true
+```

test/haveSameContents.test.js

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+const {haveSameContents} = require('./_30s.js');
+
+test('haveSameContents is a Function', () => {
+  expect(haveSameContents).toBeInstanceOf(Function);
+});
+test('returns true for arrays with same contents', () => {
+  expect(haveSameContents([1, 2, 3], [2, 3, 1])).toBeTruthy();
+});
+test('returns false for arrays with different contents', () => {
+  expect(haveSameContents([1, 2], [2, 3, 1])).toBeFalsy();
+});
+test('returns false for arrays with different contents', () => {
+  expect(haveSameContents([1, 2, 3], [2, 1])).toBeFalsy();
+});
+test('returns false for arrays with different contents', () => {
+  expect(haveSameContents([1, 2, 3], [2, 1, 6])).toBeFalsy();
+});