From 416d89f10b6dbcf256f0a03c5ad041114f72acd0 Mon Sep 17 00:00:00 2001
From: TK <leandrotk100@gmail.com>
Date: Fri, 19 Jan 2024 16:04:15 -0300
Subject: [PATCH] *

---
 .../js-coding-questions/flatten/flatten.js    | 71 +++++++++++++++++++
 1 file changed, 71 insertions(+)
 create mode 100644 coding_interviews/bigfrontend/js-coding-questions/flatten/flatten.js

diff --git a/coding_interviews/bigfrontend/js-coding-questions/flatten/flatten.js b/coding_interviews/bigfrontend/js-coding-questions/flatten/flatten.js
new file mode 100644
index 0000000..9e48359
--- /dev/null
+++ b/coding_interviews/bigfrontend/js-coding-questions/flatten/flatten.js
@@ -0,0 +1,71 @@
+/**
+ * Write a flatten function that takes in a value and returns a flattened version of that value.
+ * For the purpose of this problem, a flattened value is defined as follows:
+ * Primitive values should be left unchanged.
+ * Nested arrays should have their values brought up to the top level array. For example, [1, 2, [3, 4, [5, 6]]] would be flattened to [1, 2, 3, 4, 5, 6].
+ * Nested objects should have their key-value pairs brought up to the top level object. For example, {a: 1, b: {c: 2, d: 3, e: {f: 4}}} would be flattened to {a: 1, c: 2, d: 3, f: 4}. Note that this means the keys "b" and "e" were completely removed, since their values were flattened to the top level. In the event of a key collision (e.g. {a: 1, b: {a: 2}}), any associated value can be used.
+ * Arrays nested in objects and objects nested in arrays should be flattened. For example, {a: [1, 2, [3, 4]]} would be flattened to {a: [1, 2, 3, 4]}, and [{a: 1, b: {c: 2, d: 3}}] would be flattened to [{a: 1, c: 2, d: 3}].
+ * For simplicity, you can assume the value as well as any nested values will not be functions. Additionally, you can assume that all object keys are strings. Your solution can return a flattened value in place, or it can return a new value, either is acceptable.
+ */
+
+function flatten(value) {
+  if (value === null) {
+    return value;
+  }
+
+  if (Array.isArray(value)) {
+    return value.reduce((array, v) => {
+      if (Array.isArray(v)) {
+        return [...array, ...flatten(v)];
+      }
+
+      if (v === null) {
+        return array;
+      }
+
+      if (typeof v === 'object') {
+        return [...array, flatten(v)];
+      }
+
+      return [...array, v];
+    }, []);
+  }
+
+  if (typeof value === 'object') {
+    return Object.entries(value).reduce((obj, [key, val]) => {
+      if (val === null) {
+        return {
+          ...obj,
+          [key]: val,
+        };
+      }
+
+      if (typeof val === 'object') {
+        const flattedObj = flatten(val);
+
+        if (JSON.stringify(flattedObj) === '{}') {
+          return obj;
+        }
+
+        if (Array.isArray(val)) {
+          return {
+            ...obj,
+            [key]: flattedObj,
+          };
+        }
+
+        return {
+          ...obj,
+          ...flattedObj,
+        };
+      }
+
+      return {
+        ...obj,
+        [key]: val,
+      };
+    }, {});
+  }
+
+  return value;
+}