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Basic Types
TypeScript includes primitive types (string, number, boolean, null, undefined, symbol, bigint), array types, tuple types, object types, and special types like any, unknown, void, and never.
Primitive Types:
string: Text valuesnumber: All numbers (integer and float)boolean: true/falsenull / undefined: Absence of valuesymbol: Unique identifiersbigint: Large integersArray Types:
number[] or Array<number>Object Types:
Special Types:
any: Opt-out of type checkingunknown: Type-safe any (must narrow before use)void: No return valuenever: Never returns (throws/infinite loop)// Primitive types
let name: string = 'Alice';
let age: number = 25;
let isActive: boolean = true;
let nothing: null = null;
let notDefined: undefined = undefined;
// Number includes all numeric types
let decimal: number = 10;
let float: number = 3.14;
let hex: number = 0xff;
let binary: number = 0b1010;
// BigInt for large integers
let bigNumber: bigint = 9007199254740991n;
// Symbol
const uniqueKey: symbol = Symbol('description');Typing form field values with proper primitives and using union types for validation states
Mapping database column types to TypeScript primitives for type-safe ORM queries
Defining precise types for API payloads including nullable fields and optional properties
Build a calculator that uses TypeScript types to prevent invalid operations like dividing by a string
Implement a state machine for order status using union types and never-based exhaustive checking