feat: integer

README.md

@@ -110,6 +110,18 @@ type B = '' extends `${infer Head}${infer Tail}` ? 1 : 2
 
 #### `Uncapitalize`会将给定字符串的第一个字符小写
 
+#### 将数字类型的 1.0 转换为字符串，会得到 "1"
+
+```ts
+type NumberToString<T extends number> = `${T}`
+
+type A1 = NumberToString<1.1>;
+// type A1 = "1.1"
+
+type A2 = NumberToString<1.0>
+// type A2 = "1"
+```
+
 ### never
 
 #### 如何判断`never`

src/10969-medium-integer.ts

@@ -0,0 +1,38 @@
+// ============= Test Cases =============
+import type { Equal, Expect } from './test-utils'
+import { ExpectFalse, NotEqual } from './test-utils'
+
+let x = 1
+let y = 1 as const
+
+type cases1 = [
+  Expect<Equal<Integer<1>, 1>>,
+  Expect<Equal<Integer<1.1>, never>>,
+  Expect<Equal<Integer<1.0>, 1>>,
+  Expect<Equal<Integer<1.0>, 1>>,
+  Expect<Equal<Integer<0.5>, never>>,
+  Expect<Equal<Integer<28.0>, 28>>,
+  Expect<Equal<Integer<28.101>, never>>,
+  Expect<Equal<Integer<typeof x>, never>>,
+  Expect<Equal<Integer<typeof y>, 1>>
+]
+
+// ============= Your Code Here =============
+// type Integer<T extends number> = `${T}` extends `${infer F}.${infer R}`
+//   ? R[number] extends 0
+//     ? F
+//     : never
+//   : Equal<T, number> extends true
+//   ? never
+//   : T
+
+type Integer<T extends string | number> = number extends T
+  ? never
+  : `${T}` extends `${string}.${string}`
+  ? never
+  : T
+
+type NumberToString<T extends number> = `${T}`
+
+type A1 = NumberToString<1.1>
+type A2 = NumberToString<1.0>