From 660ac2a05aaecfc7cf54f924134ac1467578a520 Mon Sep 17 00:00:00 2001
From: djalmajr <djalmajr@gmail.com>
Date: Sun, 16 Apr 2023 18:53:19 -0300
Subject: [PATCH] Added groupBy

---
 src/groupBy.ts | 20 ++++++++++++++++++++
 src/index.ts   |  1 +
 2 files changed, 21 insertions(+)
 create mode 100644 src/groupBy.ts

diff --git a/src/groupBy.ts b/src/groupBy.ts
new file mode 100644
index 0000000..7967c8d
--- /dev/null
+++ b/src/groupBy.ts
@@ -0,0 +1,20 @@
+import { curry } from './curry';
+import { Obj } from './types';
+
+interface GroupByFn {
+  <T = unknown>(fn: (a: T) => unknown): (arr: T[]) => Obj<T[]>;
+  <T = unknown>(fn: (a: T) => unknown, arr: T[]): Obj<T[]>;
+}
+
+/**
+ * TODO: adicionar documentação
+ */
+export const groupBy = curry((fn: Function, items: unknown[]) => {
+  const res = {} as Obj;
+  for (const item of items) {
+    const key = fn(item);
+    res[key] ||= [];
+    res[key].push(item);
+  }
+  return res;
+}) as GroupByFn;
diff --git a/src/index.ts b/src/index.ts
index 955863d..e07b0fd 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -22,6 +22,7 @@ export * from './flow';
 export * from './formatCurrency';
 export * from './formatPhone';
 export * from './get';
+export * from './groupBy';
 export * from './groupByEveryN';
 export * from './includes';
 export * from './isArray';