From 74b0bbd51016d12fdc88d151db83d980d9ab5c34 Mon Sep 17 00:00:00 2001
From: Kimbrian Marshall <kimbrian.marshall@brik.id>
Date: Tue, 2 Jul 2024 15:31:48 +0700
Subject: [PATCH] feat(array): add mapify

---
 benchmarks/array/mapify.bench.ts | 28 +++++++++++++++++++++++
 docs/array/mapify.mdx            | 38 ++++++++++++++++++++++++++++++++
 src/array/mapify.ts              |  9 ++++++++
 src/mod.ts                       |  2 ++
 tests/array/mapify.test.ts       | 36 ++++++++++++++++++++++++++++++
 5 files changed, 113 insertions(+)
 create mode 100644 benchmarks/array/mapify.bench.ts
 create mode 100644 docs/array/mapify.mdx
 create mode 100644 src/array/mapify.ts
 create mode 100644 tests/array/mapify.test.ts

diff --git a/benchmarks/array/mapify.bench.ts b/benchmarks/array/mapify.bench.ts
new file mode 100644
index 00000000..0202b2a1
--- /dev/null
+++ b/benchmarks/array/mapify.bench.ts
@@ -0,0 +1,28 @@
+import * as _ from 'radashi'
+import { bench } from 'vitest'
+
+describe('mapify', () => {
+  bench('with full list and identity value function', () => {
+    const list = [
+      { id: 'a', word: 'hello' },
+      { id: 'b', word: 'bye' },
+      { id: 'c', word: 'oh' },
+      { id: 'd', word: 'hey' },
+      { id: 'e', word: 'ok' },
+    ]
+    _.objectify(
+      list,
+      x => x.id,
+      x => x,
+    )
+  })
+
+  bench('with empty list', () => {
+    _.objectify(
+      [],
+      (x: any) => x.id,
+      x => x,
+    )
+  })
+})
+
diff --git a/docs/array/mapify.mdx b/docs/array/mapify.mdx
new file mode 100644
index 00000000..3257d085
--- /dev/null
+++ b/docs/array/mapify.mdx
@@ -0,0 +1,38 @@
+---
+title: mapify
+group: "Array"
+description: Convert an array to a map
+---
+
+## Basic usage
+
+Given an array of items, create a map with keys and values mapped by given
+functions. First argument is the array to map. The second argument is the
+function to determine the key for each item. The third argument is optional and
+determines the value for each item.
+
+```ts
+import * as _ from "radashi";
+
+const fish = [
+  {
+    name: "Marlin",
+    weight: 105,
+  },
+  {
+    name: "Bass",
+    weight: 8,
+  },
+  {
+    name: "Trout",
+    weight: 13,
+  },
+];
+
+_.mapify(fish, f => f.name); // => Map(3) {'Marlin' => { name: 'Marlin', weight: 105 }, 'Bass' => { name: 'Bass', weight: 8 }, 'Trout' => { name: 'Trout', weight: 13 }}
+_.mapify(
+  fish,
+  f => f.name,
+  f => f.weight
+); // => Map(3) { 'Marlin' => 105, 'Bass' => 8, 'Trout' => 13 }
+```
diff --git a/src/array/mapify.ts b/src/array/mapify.ts
new file mode 100644
index 00000000..961be93d
--- /dev/null
+++ b/src/array/mapify.ts
@@ -0,0 +1,9 @@
+export function mapify<T, Key, Value = T>(
+  array: readonly T[],
+  getKey: (item: T) => Key,
+  getValue: (item: T) => Value = item => item as unknown as Value,
+): Map<Key, Value> {
+	const map: Map<Key, Value> = new Map();
+	array.forEach(item => map.set(getKey(item), getValue(item)))
+  return map;
+}
diff --git a/src/mod.ts b/src/mod.ts
index bbef98d5..590d2fa2 100644
--- a/src/mod.ts
+++ b/src/mod.ts
@@ -11,6 +11,7 @@ export * from './array/intersects.ts'
 export * from './array/iterate.ts'
 export * from './array/last.ts'
 export * from './array/list.ts'
+export * from './array/mapify.ts'
 export * from './array/max.ts'
 export * from './array/merge.ts'
 export * from './array/min.ts'
@@ -105,3 +106,4 @@ export * from './typed/isPrimitive.ts'
 export * from './typed/isPromise.ts'
 export * from './typed/isString.ts'
 export * from './typed/isSymbol.ts'
+
diff --git a/tests/array/mapify.test.ts b/tests/array/mapify.test.ts
new file mode 100644
index 00000000..d4c106ac
--- /dev/null
+++ b/tests/array/mapify.test.ts
@@ -0,0 +1,36 @@
+import * as _ from 'radashi'
+
+describe('mapify', () => {
+  const list = [
+    { id: 'a', word: 'hello' },
+    { id: 'b', word: 'bye' },
+    { id: 'c', word: 'oh' },
+    { id: 'd', word: 'hey' },
+    { id: 'e', word: 'ok' },
+  ]
+  test('returns correct map of values', () => {
+    const result = _.mapify(
+      list,
+      x => x.id,
+      x => x,
+    )
+    expect(result).toBeTypeOf(typeof new Map())
+    expect(result.size).toBe(5)
+    expect(result.get("a")?.word).toBe('hello')
+    expect(result.get("b")?.word).toBe('bye')
+  })
+  test('does not fail on empty input list', () => {
+    const result = _.mapify(
+      [],
+      (x: any) => x.id,
+      x => x,
+    )
+    expect(result).toBeTypeOf(typeof new Map())
+  })
+  test('defaults value to array item', () => {
+    const result = _.mapify(list.slice(0, 1), x => x.id)
+    expect(result).toBeTypeOf(typeof new Map())
+    expect(result.size).toBe(1)
+    expect(result.get("a")?.word).toBe('hello')
+  })
+})