Adding content to 111-utility-types

src/roadmaps/typescript/content/111-utility-types/100-partial.md

@@ -1 +1,30 @@
-# Partial
+# Partial
+
+The Partial type in TypeScript allows you to make all properties of a type optional. This is useful when you need to create an object with only a subset of the properties of an existing type.
+
+Here's an example of using the Partial type in TypeScript:
+
+    ```
+    interface User {
+    name: string;
+    age: number;
+    email: string;
+    }
+
+    function createUser(user: Partial<User>): User {
+    return {
+        name: 'John Doe',
+        age: 30,
+        email: 'john.doe@example.com',
+        ...user
+    };
+    }
+
+    const newUser = createUser({ name: 'Jane Doe' });
+    console.log(newUser);
+    // Output: { name: 'Jane Doe', age: 30, email: 'john.doe@example.com' }
+    ```
+
+Learn more from the following links:
+
+- [Partial<Type>](https://www.typescriptlang.org/docs/handbook/utility-types.html#partialtype)

src/roadmaps/typescript/content/111-utility-types/101-pick.md

@@ -1 +1,26 @@
-# Pick
+# Pick
+
+Pick constructs a type by picking the set of properties Keys (string literal or union of string literals) from Type.
+
+    ```
+    interface Todo {
+    title: string;
+    description: string;
+    completed: boolean;
+    }
+    
+    type TodoPreview = Pick<Todo, "title" | "completed">;
+    
+    const todo: TodoPreview = {
+    title: "Clean room",
+    completed: false,
+    };
+    
+    todo;
+    
+    const todo: TodoPreview
+    ```
+
+Learn more from the following links:
+
+- [Pick<Type, Keys>](https://www.typescriptlang.org/docs/handbook/utility-types.html#picktype-keys)

src/roadmaps/typescript/content/111-utility-types/102-omit.md

@@ -1 +1,40 @@
-# Omit
+# Omit
+
+Omit constructs a type by picking all properties from Type and then removing Keys (string literal or union of string literals).
+
+
+    ```
+    interface Todo {
+    title: string;
+    description: string;
+    completed: boolean;
+    createdAt: number;
+    }
+    
+    type TodoPreview = Omit<Todo, "description">;
+    
+    const todo: TodoPreview = {
+    title: "Clean room",
+    completed: false,
+    createdAt: 1615544252770,
+    };
+    
+    todo;
+    
+    const todo: TodoPreview
+    
+    type TodoInfo = Omit<Todo, "completed" | "createdAt">;
+    
+    const todoInfo: TodoInfo = {
+    title: "Pick up kids",
+    description: "Kindergarten closes at 5pm",
+    };
+    
+    todoInfo;
+    
+    const todoInfo: TodoInfo
+    ```
+
+Learn more from the following links:
+
+- [Omit<Type, Keys>](https://www.typescriptlang.org/docs/handbook/utility-types.html#omittype-keys)

src/roadmaps/typescript/content/111-utility-types/103-readonly.md

@@ -1 +1,20 @@
-# Readonly
+# Readonly
+
+Readonly constructs a type with all properties of Type set to readonly, meaning the properties of the constructed type cannot be reassigned.
+
+    ```
+    interface Todo {
+    title: string;
+    }
+    
+    const todo: Readonly<Todo> = {
+    title: "Delete inactive users",
+    };
+    
+    todo.title = "Hello";
+    Cannot assign to 'title' because it is a read-only property.
+    ```
+
+Learn more from the following links:
+
+- [Readonly<Type>](https://www.typescriptlang.org/docs/handbook/utility-types.html#readonlytype)

src/roadmaps/typescript/content/111-utility-types/104-record.md

@@ -1 +1,26 @@
-# Record
+# Record
+
+Record constructs an object type whose property keys are Keys and whose property values are Type. This utility can be used to map the properties of a type to another type.
+
+    ```
+    interface CatInfo {
+    age: number;
+    breed: string;
+    }
+    
+    type CatName = "miffy" | "boris" | "mordred";
+    
+    const cats: Record<CatName, CatInfo> = {
+    miffy: { age: 10, breed: "Persian" },
+    boris: { age: 5, breed: "Maine Coon" },
+    mordred: { age: 16, breed: "British Shorthair" },
+    };
+    
+    cats.boris;
+    
+    const cats: Record<CatName, CatInfo>
+    ```
+
+Learn more from the following links:
+
+- [Record<Keys, Type>](https://www.typescriptlang.org/docs/handbook/utility-types.html#recordkeys-type)

src/roadmaps/typescript/content/111-utility-types/105-exclude.md

@@ -1 +1,19 @@
-# Exclude
+# Exclude
+
+Exclude constructs a type by excluding from UnionType all union members that are assignable to ExcludedMembers.
+
+    ```
+    type T0 = Exclude<"a" | "b" | "c", "a">;
+        
+    type T0 = "b" | "c"
+    type T1 = Exclude<"a" | "b" | "c", "a" | "b">;
+        
+    type T1 = "c"
+    type T2 = Exclude<string | number | (() => void), Function>;
+        
+    type T2 = string | number
+    ```
+
+Learn more from the following links:
+
+- [Exclude<UnionType, ExcludedMembers>](https://www.typescriptlang.org/docs/handbook/utility-types.html#excludeuniontype-excludedmembers)

src/roadmaps/typescript/content/111-utility-types/106-extract.md

@@ -1 +1,16 @@
-# Extract
+# Extract
+
+Extract constructs a type by extracting from Type all union members that are assignable to Union.
+
+    ```
+    type T0 = Extract<"a" | "b" | "c", "a" | "f">;
+        
+    type T0 = "a"
+    type T1 = Extract<string | number | (() => void), Function>;
+        
+    type T1 = () => void
+    ```
+
+Learn more from the following links:
+
+- [Extract<Type, Union>](https://www.typescriptlang.org/docs/handbook/utility-types.html#extracttype-union)

src/roadmaps/typescript/content/111-utility-types/107-non-nullable.md

@@ -1 +1,16 @@
-# Non nullable
+# Non Nullable
+
+Nun Nullable constructs a type by excluding null and undefined from Type.
+
+    ```
+    type T0 = NonNullable<string | number | undefined>;
+        
+    type T0 = string | number
+    type T1 = NonNullable<string[] | null | undefined>;
+        
+    type T1 = string[]
+    ```
+
+Learn more from the following links:
+
+- [NonNullable<Type>](https://www.typescriptlang.org/docs/handbook/utility-types.html#nonnullabletype)

src/roadmaps/typescript/content/111-utility-types/108-parameters.md

@@ -1 +1,38 @@
-# Parameters
+# Parameters
+
+Parameters constructs a tuple type from the types used in the parameters of a function type Type.
+
+    ```
+    declare function f1(arg: { a: number; b: string }): void; 
+    type T0 = Parameters<() => string>;
+    type T0 = []
+    type T1 = Parameters<(s: string) => void>;
+    type T1 = [s: string]
+    type T2 = Parameters<<T>(arg: T) => T>;
+    type T2 = [arg: unknown]
+    type T3 = Parameters<typeof f1>;
+        
+    type T3 = [arg: {
+        a: number;
+        b: string;
+    }]
+    type T4 = Parameters<any>;
+        
+    type T4 = unknown[]
+    type T5 = Parameters<never>;
+        
+    type T5 = never
+    type T6 = Parameters<string>;
+    Type 'string' does not satisfy the constraint '(...args: any) => any'.
+        
+    type T6 = never
+    type T7 = Parameters<Function>;
+    Type 'Function' does not satisfy the constraint '(...args: any) => any'.
+    Type 'Function' provides no match for the signature '(...args: any): any'.
+        
+    type T7 = never
+    ```
+
+Learn more from the following links:
+
+- [Parameters<Type>](https://www.typescriptlang.org/docs/handbook/utility-types.html#parameterstype)

src/roadmaps/typescript/content/111-utility-types/109-return-type.md

@@ -1 +1,44 @@
-# Return type
+# Return type
+
+Return type constructs a type consisting of the return type of function Type.
+
+    ```
+    declare function f1(): { a: number; b: string }; 
+    type T0 = ReturnType<() => string>;
+        
+    type T0 = string
+    type T1 = ReturnType<(s: string) => void>;
+        
+    type T1 = void
+    type T2 = ReturnType<<T>() => T>;
+        
+    type T2 = unknown
+    type T3 = ReturnType<<T extends U, U extends number[]>() => T>;
+        
+    type T3 = number[]
+    type T4 = ReturnType<typeof f1>;
+        
+    type T4 = {
+        a: number;
+        b: string;
+    }
+    type T5 = ReturnType<any>;
+        
+    type T5 = any
+    type T6 = ReturnType<never>;
+        
+    type T6 = never
+    type T7 = ReturnType<string>;
+    Type 'string' does not satisfy the constraint '(...args: any) => any'.
+        
+    type T7 = any
+    type T8 = ReturnType<Function>;
+    Type 'Function' does not satisfy the constraint '(...args: any) => any'.
+    Type 'Function' provides no match for the signature '(...args: any): any'.
+        
+    type T8 = any
+    ```
+
+Learn more from the following links:
+
+- [ReturnType<Type>](https://www.typescriptlang.org/docs/handbook/utility-types.html#returntypetype)

src/roadmaps/typescript/content/111-utility-types/110-instance-type.md

@@ -1 +1,34 @@
-# Instance type
+# Instance type
+
+
+This type constructs a type consisting of the instance type of a constructor function in Type.
+
+    ```
+    class C {
+    x = 0;
+    y = 0;
+    }
+    
+    type T0 = InstanceType<typeof C>;
+        
+    type T0 = C
+    type T1 = InstanceType<any>;
+        
+    type T1 = any
+    type T2 = InstanceType<never>;
+        
+    type T2 = never
+    type T3 = InstanceType<string>;
+    Type 'string' does not satisfy the constraint 'abstract new (...args: any) => any'.
+        
+    type T3 = any
+    type T4 = InstanceType<Function>;
+    Type 'Function' does not satisfy the constraint 'abstract new (...args: any) => any'.
+    Type 'Function' provides no match for the signature 'new (...args: any): any'.
+        
+    type T4 = any
+    ```
+
+Learn more from the following links:
+
+- [InstanceType<Type>](https://www.typescriptlang.org/docs/handbook/utility-types.html#instancetypetype)

src/roadmaps/typescript/content/111-utility-types/111-awaited.md

@@ -1 +1,21 @@
-# Awaited
+# Awaited
+
+This type is meant to model operations like await in async functions, or the .then() method on Promises - specifically, the way that they recursively unwrap Promises.
+
+    ```
+    type A = Awaited<Promise<string>>;
+        
+    type A = string
+    
+    type B = Awaited<Promise<Promise<number>>>;
+        
+    type B = number
+    
+    type C = Awaited<boolean | Promise<number>>;
+        
+    type C = number | boolean
+    ```
+
+Learn more from the following links:
+
+- [Awaited<Type>](https://www.typescriptlang.org/docs/handbook/utility-types.html#awaitedtype)

src/roadmaps/typescript/content/111-utility-types/index.md

@@ -1 +1,13 @@
-# Utility types
+# Utility Types
+
+TypeScript provides several utility types that can be used to manipulate and transform existing types. Here are some of the most common ones:
+
+1. Partial: makes all properties of a type optional.
+2. Readonly: makes all properties of a type read-only.
+3. Pick: allows you to pick specific properties from a type.
+4. Omit: allows you to omit specific properties from a type.
+5. Exclude: creates a type that is the set difference of A and B.
+
+Learn more from the following links:
+
+- [TypeScript - Utility Types](https://www.typescriptlang.org/docs/handbook/utility-types.html)