Majid Abbasi’s Post

⚡ JavaScript & TypeScript Daily Refresher #85 👉 What is a predicate in TypeScript? 💡 A predicate is a special return type used in custom type guards — it tells TypeScript that a function checks a specific type. Example: function isString(value: unknown): value is string { return typeof value === "string"; } ✨ I post daily JS/TS refreshers — follow for the next one! #JavaScript #TypeScript #TypeGuards #WebDevelopment

⚡ JavaScript & TypeScript Daily Refresher #77 👉 What is the return type of a setter function in TypeScript? 💡 Setter functions should not have a return type at all — they’re meant only to update a property’s value, not return anything. ✨ I post daily JS/TS refreshers — follow for the next one! #JavaScript #TypeScript #OOP #WebDevelopment

⚡ JavaScript & TypeScript Daily Refresher #88 👉 What is a “never check” in TypeScript? 💡 A never check happens when TypeScript confirms that all possible cases of a union are handled — anything left falls into the never type, helping you catch missing branches at compile time. ✨ I post daily JS/TS refreshers — follow for the next one! #JavaScript #TypeScript #AdvancedTypes #WebDevelopment

⚡ JavaScript & TypeScript Daily Refresher #83 👉 How do you check if TypeA is assignable to TypeB in TypeScript? 💡 Use a conditional type — for example: type Check = TypeA extends TypeB ? TypeC : TypeD This checks assignability at the type level and picks the result accordingly. ✨ I post daily JS/TS refreshers — follow for the next one! #JavaScript #TypeScript #AdvancedTypes #WebDevelopment

⚡ JavaScript & TypeScript Daily Refresher #75 👉 How are classes different in TypeScript and JavaScript? 💡 They work the same at runtime — both compile to JavaScript classes. But TypeScript adds type checking, access modifiers, and interfaces, making class-based development more structured and safer. ✨ I post daily JS/TS refreshers — follow for the next one! #JavaScript #TypeScript #OOP #WebDevelopment

⚡ JavaScript & TypeScript Daily Refresher #64 👉 What happens to default parameter values after TypeScript compiles to JavaScript? 💡 TypeScript converts them into plain JS checks. It adds an if statement to see if the argument is undefined, and if so, assigns the default value — ensuring consistent behavior at runtime. ✨ I post daily JS/TS refreshers — follow for the next one! #JavaScript #TypeScript #Compilation #WebDevelopment

⚡ JavaScript & TypeScript Daily Refresher #74 👉 What are the most important components of classes in JavaScript and TypeScript? 💡 Classes mainly include properties, constructors, and methods. In TypeScript, you can also define access modifiers like public, private, and protected for better structure and encapsulation. ✨ I post daily JS/TS refreshers — follow for the next one! #JavaScript #TypeScript #OOP #WebDevelopment

⚡ JavaScript & TypeScript Daily Refresher #62 👉 When do you use export default and when export in TypeScript? 💡 Use export for named exports when a file contains multiple items. Use export default for a single main value — like React components or utility modules with one primary function. ✨ I post daily JS/TS refreshers — follow for the next one! #JavaScript #TypeScript #React #WebDevelopment

⚡ JavaScript & TypeScript Daily Refresher #63 👉 What are some bad practices in TypeScript? 💡 ❌ Adding type annotations everywhere — it reduces readability when inference already works. ❌ Overusing any — it defeats the purpose of TypeScript’s type safety. ✨ I post daily JS/TS refreshers — follow for the next one! #JavaScript #TypeScript #CleanCode #BestPractices

⚡ JavaScript & TypeScript Daily Refresher #86 👉 I have a type that’s a union of multiple types — what’s the side effect of using it? 💡 Unions can cause more complex narrowing because TypeScript must consider all possible types, which can lead to extra checks before accessing properties or calling methods. ✨ I post daily JS/TS refreshers — follow for the next one! #JavaScript #TypeScript #TypeNarrowing #WebDevelopment