Objects, Type Aliases, Readonly, & Optional

AritraC1 · AritraC1 · commit 44e4367d69d6 · 2025-05-28T10:25:15.000+05:30
diff --git a/TS/Basics/objects.ts b/TS/Basics/objects.ts
@@ -0,0 +1,64 @@
+// Objects
+
+const user = {
+    name: "Tony",
+    email: "ironman@avengers.com",
+    isActive: true
+}
+
+// Weird Behavior
+// function createUser({name: string, isPaid: boolean}){}
+// let newUser = {name: "Peter", isPaid: false, email: "t@t.com"}
+// createUser(newUser);
+
+// Better way
+function createCourse ():{name: string, price: number}{
+    return {name: "Full Stack Web Development", price: 599}
+}
+
+// Type Aliases
+
+type User = {
+    name: string;
+    email: string;
+    isActive: boolean
+}
+
+function createUser(user: User){}
+
+createUser({name: "", email: "", isActive: false})
+
+// READONLY (Scenario Based)
+type UserDetails = {
+    readonly _id: string; // wont be able to change the value of _id down the road
+    name: string;
+    email: string;
+    isActive: boolean;
+    creditCardDetails?: number // optional (?)
+}
+
+let newUser: UserDetails = {
+    _id: "12345",
+    name: "Peter",
+    email: "parker@avengers.com",
+    isActive: true,
+}
+
+type cardNumber = {
+    cardNumberVal: string
+}
+
+type cardDate = {
+    cardDateValue: string
+}
+
+// Using existing types to define another type
+type cardDetails = cardNumber & cardDate & {
+    cvv: number
+}
+
+newUser.email = "pete@avengers.com";
+// newUser._id = "234"; // Cannot assign to '_id' because it is a read-only property.
+
+
+export {}
