From 00f824b5bd66ec7d15b4e2927ba12e4e4f7f987f Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Thu, 6 Aug 2020 20:50:44 +0800
Subject: [PATCH] feat(question): add #62 - Type Lookup (#63)

Co-authored-by: Anthony Fu <11247099+antfu@users.noreply.github.com>
---
 questions/62-medium-type-lookup/README.md     | 18 ++++++++++++++++++
 questions/62-medium-type-lookup/info.yml      |  7 +++++++
 questions/62-medium-type-lookup/template.ts   |  1 +
 questions/62-medium-type-lookup/test-cases.ts | 19 +++++++++++++++++++
 4 files changed, 45 insertions(+)
 create mode 100644 questions/62-medium-type-lookup/README.md
 create mode 100644 questions/62-medium-type-lookup/info.yml
 create mode 100644 questions/62-medium-type-lookup/template.ts
 create mode 100644 questions/62-medium-type-lookup/test-cases.ts

diff --git a/questions/62-medium-type-lookup/README.md b/questions/62-medium-type-lookup/README.md
new file mode 100644
index 00000000..faa7105b
--- /dev/null
+++ b/questions/62-medium-type-lookup/README.md
@@ -0,0 +1,18 @@
+Sometimes, you may want to lookup for a type in a union to by their attributes. 
+
+In this challenge, I would like to have get the couponing type by searching for the common `type` field in the union `Cat | Dog`. In other words, I will expect to get `Dog` for `LookUp<Dog | Cat, 'dog'>` and `Cat` for `LookUp<Dog | Cat, 'cat'>` in the following example.
+
+```ts
+interface Cat {
+  type: 'cat'
+  breeds: 'Abyssinian' | 'Shorthair' | 'Curl' | 'Bengal'
+}
+
+interface Dog {
+  type: 'dog'
+  breeds: 'Hound' | 'Brittany' | 'Bulldog' | 'Boxer'
+  color: 'brown' | 'white' | 'black'
+}
+
+const MyDog = LookUp<Cat | Dog, 'dog'> // expected to be `Dog`
+```
diff --git a/questions/62-medium-type-lookup/info.yml b/questions/62-medium-type-lookup/info.yml
new file mode 100644
index 00000000..3c2b7bc0
--- /dev/null
+++ b/questions/62-medium-type-lookup/info.yml
@@ -0,0 +1,7 @@
+difficulty: medium
+title: Type Lookup
+tags: 'union, map'
+author:
+  github: antfu
+  name: Anthony Fu
+
diff --git a/questions/62-medium-type-lookup/template.ts b/questions/62-medium-type-lookup/template.ts
new file mode 100644
index 00000000..af722474
--- /dev/null
+++ b/questions/62-medium-type-lookup/template.ts
@@ -0,0 +1 @@
+type LookUp<U, T> = any
diff --git a/questions/62-medium-type-lookup/test-cases.ts b/questions/62-medium-type-lookup/test-cases.ts
new file mode 100644
index 00000000..0d9c5c2e
--- /dev/null
+++ b/questions/62-medium-type-lookup/test-cases.ts
@@ -0,0 +1,19 @@
+import { Equal, Expect } from '@type-challenges/utils'
+
+interface Cat {
+  type: 'cat'
+  breeds: 'Abyssinian' | 'Shorthair' | 'Curl' | 'Bengal'
+}
+
+interface Dog {
+  type: 'dog'
+  breeds: 'Hound' | 'Brittany' | 'Bulldog' | 'Boxer'
+  color: 'brown' | 'white' | 'black'
+}
+
+type Animal = Cat | Dog
+
+type cases = [
+  Expect<Equal<LookUp<Animal, 'dog'>, Dog>>,
+  Expect<Equal<LookUp<Animal, 'cat'>, Cat>>,
+]