Typescript terms
JavaScript with a safety net and a much better IDE experience
TypeScript adds a powerful static type system to JavaScript, catching errors at compile time and making large codebases dramatically easier to maintain and refactor. This category covers type primitives, generics, utility types, declaration files, strict mode, and the patterns that make TypeScript an upgrade rather than just added ceremony.
Discriminated Unions 2.0 A union of types that each carry a shared literal field (the discriminant) allowing TypeScript to narrow exhaustively — the canonical way to model mutually exclusive states.
4w ago
typescript intermediate
Type Guards & Narrowing 2.0 Type guards are expressions that narrow a union type to a more specific type at runtime — telling TypeScript exactly which branch of a union you're in.
4w ago
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const Type Parameters (TS 5.0) 5.0
TypeScript 5.0 const type parameters infer literal types instead of widened types — const T extends string[] infers ['a','b'] not string[].
2mo ago
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Exhaustive Checks with never
Using the 'never' type in a default branch to make TypeScript error at compile time if a union type is not fully handled — ensures every new variant of a type forces a matching handler to be written.
2mo ago
typescript intermediate
TypeScript Function Overloads
TypeScript function overloads allow a single function to accept different argument shapes and return different types based on which overload signature matches — providing precise type checking that union types alone cannot express.
2mo ago
typescript intermediate
satisfies Operator (TS 4.9) 4.9
satisfies validates that a value matches a type without widening the inferred type — keeping precise literal types while checking against an interface.
2mo ago
typescript intermediate
TypeScript Enums vs Const Enums vs Union Types 2.0
Three ways to define a set of named constants in TypeScript — regular enums emit JavaScript, const enums are inlined at compile time, and union types are the idiomatic zero-cost alternative.
2mo ago
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TypeScript Modules & Namespaces 2.0
ES modules (import/export) are the modern standard — namespaces are legacy for global scripts and ambient declarations only.
2mo ago
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TypeScript vs PHP Type System 4.0
TypeScript uses structural typing (shape compatibility); PHP uses nominal typing (explicit implements). TypeScript infers types; PHP requires annotations. Both support generics (PHP via PHPDoc).
2mo ago
typescript intermediate
tsconfig.json 4.0
The TypeScript compiler configuration file — controlling which files are compiled, what JavaScript version is targeted, strictness settings, and module resolution.
2mo ago
typescript intermediate
TypeScript Interfaces vs Type Aliases 2.0 Both define object shapes, but interfaces are open (mergeable via declaration merging) while type aliases are closed — types are more flexible for unions and computed types.
2mo ago
typescript intermediate
TypeScript Strict Mode 2.3
A tsconfig flag that enables the strictest type-checking options — strictNullChecks, noImplicitAny, and others — catching the most common TypeScript pitfalls.
2mo ago
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TypeScript Type System 2.0
TypeScript adds static types to JavaScript — catching type errors at compile time rather than runtime, while remaining a superset that compiles to plain JavaScript.
2mo ago
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TypeScript Utility Types 2.1 Built-in generic types that transform existing types — Partial, Required, Pick, Omit, Record, Readonly, ReturnType — eliminating the need to manually duplicate type definitions.
2mo ago
typescript intermediate