💫 workflow(3-4):

Author: 2495867729

README.md

@@ -24,4 +24,9 @@
       - /medium/20 
       - /medium/106
       - /medium/108
-      - /medium/110 *
+      - /medium/110 *
+      - /medium/116
+      - /medium/119
+      - /medium/296 *
+      - /medium/298 *
+      - /medium/459 *

medium/116-Replace.ts

@@ -0,0 +1,14 @@
+/*
+ * @Date: 2022-03-04
+ * @Description: Replace
+ */
+
+type Replace<
+    T extends string,
+    K extends string,
+    U extends string
+> = T extends `${infer S}${K}${infer R}` ? `${S}${U}${R}` : T;
+
+type replaced = Replace<"types are fun!", "fun", "awesome">; // expected to be 'types are awesome!'
+
+export {};

medium/119-ReplaceAll.ts

@@ -0,0 +1,14 @@
+/*
+ * @Date: 2022-03-04
+ * @Description: ReplaceAll
+ */
+
+type ReplaceAll<
+    T extends string,
+    K extends string,
+    U extends string
+> = T extends `${infer S}${K}${infer R}` ? ReplaceAll<`${S}${R}`, K, U> : T;
+
+type replaced = ReplaceAll<"t y p e s", " ", "">; // expected to be 'types'
+
+export {};

medium/191-AppendArgument.ts

@@ -0,0 +1,17 @@
+/*
+ * @Date: 2022-03-04
+ * @Description: Append Argument
+ */
+
+type Fn = (a: number, b: string) => number;
+
+type AppendArgument<T extends (...args: any[]) => any, K> = T extends (
+    ...args: infer R
+) => any
+    ? (...args: [...R, K]) => any
+    : never;
+
+type Result = AppendArgument<Fn, boolean>;
+// expected be (a: number, b: string, x: boolean) => number
+
+export {};

medium/296-Purmutation.ts

@@ -0,0 +1,20 @@
+/*
+ * @Date: 2022-03-04
+ * @Description: Purmutation
+ */
+
+type Permutation<T, U = T> = T extends [never]
+    ? []
+    : T extends any
+    ? [T, ...Permutation<Exclude<U, T>>]
+    : U;
+
+type perm = Permutation<"A" | "B" | "C">; // ['A', 'B', 'C'] | ['A', 'C', 'B'] | ['B', 'A', 'C'] | ['B', 'C', 'A'] | ['C', 'A', 'B'] | ['C', 'B', 'A']
+
+//type Permutation2<T, U = T> = T extends [never]
+//    ? []
+//    : T extends any
+//    ? [T, ...Permutation2<Exclude<U, T>>]
+//    : U;
+
+export {};

medium/298-LengthOfString.ts

@@ -0,0 +1,17 @@
+/*
+ * @Date: 2022-03-04
+ * @Description: Length of String
+ */
+
+type title = "title";
+
+type LengthOfString<
+    T extends string,
+    U extends string[] = []
+> = T extends `${infer F}${infer R}`
+    ? LengthOfString<R, [F, ...U]>
+    : U["length"];
+
+type x = LengthOfString<title>;
+
+export {};

medium/457-AppendToObject.ts

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+/*
+ * @Date: 2022-03-04
+ * @Description: Append to Obejct
+ */
+
+type Test = { id: "1" };
+
+type AppendToObject<
+    T extends Record<string, any>,
+    K extends string | symbol | number,
+    U extends any
+> = {
+    [P in keyof T]: T[P];
+} & Record<K, U>;
+
+type Result = AppendToObject<Test, "value", 4>; // expected to be { id: '1', value: 4 }
+
+const res: Result = {
+    id: "1",
+    value: 4,
+};
+
+type AppendToObject2<
+    T,
+    K extends string | number | symbol,
+    V extends unknown
+> = {
+    [P in keyof T | K]: P extends keyof T ? T[P] : V;
+};
+
+type Result2 = AppendToObject2<Test, "value", 4>; // expected to be { id: '1', value: 4 }
+
+const res2: Result2 = {
+    id: "1",
+    value: 4,
+};
+
+export {};

medium/459-Flattern.ts

@@ -0,0 +1,24 @@
+/*
+ * @Date: 2022-03-04
+ * @Description: Flatten
+ */
+
+type Flatten<T extends any[]> = T extends [infer F, ...infer R]
+    ? F extends any[]
+        ? R["length"] extends 0
+            ? [...Flatten<F>]
+            : [...Flatten<F>, ...Flatten<R>]
+        : [F, ...Flatten<R>]
+    : [];
+
+type flatten = Flatten<[1, 2, [3, 4], [[[5]]]]>; // [1, 2, 3, 4, 5]
+
+//type Flatten2<T extends any[]> = T extends [infer F, ...infer R]
+//    ? F extends any[]
+//        ? [...Flatten<F>, ...Flatten<R>]
+//        : [F, ...Flatten<R>]
+//    : [];
+
+//type flatten2 = Flatten2<[1, 2, [3, 4], [[[5]]]]>; // [1, 2, 3, 4, 5]
+
+export {};