update

Typescript/类型体操/day1.ts

@@ -0,0 +1,20 @@
+// type A = 1
+// type B = 2
+// type C = A extends B ? true : false
+
+// // 返回类型的函数
+// let fn = (x, y) => x + y
+// type Fn<X, Y> = X | Y
+
+// type StrOrNum = Fn<string, number>
+// type Player = Fn<'p1', 'p2'>
+
+
+// type b = number extends string ? true : false
+// 工具类
+
+// type A = string | undefined
+// type B = Exclude<A, undefined>
+
+type A = ( string | undefined | null) & {}
+type B = undefined & {}