Merge pull request #205 from KCSquid/compare-arrays

add snippet to compare two javascript arrays for equality

Author: majvax

snippets/javascript/array-manipulation/compare-arrays.md

@@ -0,0 +1,32 @@
+---
+title: Compare Arrays
+description: Deeply compares two arrays to check if they are equal to each other (supports nested arrays and objects).
+author: KCSquid
+tags: array,object,compare,equal
+---
+
+```js
+const compareArrays = (a, b) => {
+  if (!Array.isArray(a) || !Array.isArray(b) || a.length !== b.length) return false;
+  return a.every((v, i) => 
+    Array.isArray(v) && Array.isArray(b[i]) ? compareArrays(v, b[i]) :
+    typeof v === "object" && typeof b[i] === "object" ? compareObjects(v, b[i]) :
+    v === b[i]
+  );
+};
+
+const compareObjects = (a, b) => {
+  if (typeof a !== "object" || typeof b !== "object" || Object.keys(a).length !== Object.keys(b).length) return false;
+  return Object.keys(a).every(k => 
+    Array.isArray(a[k]) && Array.isArray(b[k]) ? compareArrays(a[k], b[k]) :
+    typeof a[k] === "object" && typeof b[k] === "object" ? compareObjects(a[k], b[k]) :
+    a[k] === b[k]
+  );
+};
+
+// Usage:
+compareArrays([1, 2, 3], [1, 2, 3]); // Returns: true
+compareArrays([1, 2, 3], [3, 2, 1]); // Returns: false
+compareArrays([{a:1}], [{a:1}]);     // Returns: true
+compareArrays([{a:1}], null);        // Returns: false
+```