Typescript Glossary

Browse 34 typescript terms defined in plain English, from the cultural dictionary of computing.

34 Typescript Terms

Convex
A reactive backend platform that combines a real-time database, serverless functions, and file storage into a single TypeScript-native service. Convex...
Declaration File
A TypeScript file with a .d.ts extension that provides type information for JavaScript code without containing implementation. Declaration files enable IDE...
Deno
A JavaScript/TypeScript runtime created by Ryan Dahl (who also created Node.js) to address Node's design mistakes. Built-in TypeScript support, secure by...
Discriminated Union
A union type where each member has a common literal property (the discriminant) that allows the type checker to narrow which variant is in use. Also called a...
Drizzle
A TypeScript ORM that positions itself as 'if you know SQL, you know Drizzle.' Unlike Prisma's abstracted query API, Drizzle provides a SQL-like query builder...
EdgeDB
A database that combines the reliability of PostgreSQL with a modern query language called EdgeQL, designed to replace both the ORM and raw SQL in application...
Elysia
A TypeScript web framework optimized for Bun, focused on developer experience through end-to-end type safety and exceptional performance. Elysia uses Bun's...
Generics
A language feature that lets classes, interfaces, and functions accept type parameters, enabling reusable, type-safe data structures and algorithms....
Hono
A small, fast, and ultraportable web framework for TypeScript that runs on any JavaScript runtime: Cloudflare Workers, Deno, Bun, Node.js, AWS Lambda, and...
Partial Type
A utility type (most commonly TypeScript's Partial<T>) that constructs a new type by making every property of an existing type optional, useful for update...
Path Alias
A mapping configured in a build tool or compiler (such as tsconfig.json's paths or Webpack's resolve.alias) that lets developers import modules using a short,...
Payload CMS
An open-source, code-first headless CMS and application framework built with TypeScript and Next.js. Payload defines content schemas in TypeScript...
Prisma
A next-generation ORM (Object-Relational Mapping) for Node.js and TypeScript that replaces traditional ORMs with a type-safe database client generated from a...
Strict Mode
A restricted variant of JavaScript (activated by `"use strict"`) that disables error-prone features like implicit globals, silent assignment failures, and...
Structural Subtyping
A type compatibility rule in which a type is considered a subtype of another if it has at least the same structure — the same properties or methods with...
Structural Typing
A type system where compatibility is determined by a type's structure (its properties and methods) rather than its declared name or inheritance hierarchy. If...
tRPC
A framework for building end-to-end typesafe APIs in TypeScript without code generation or schemas. tRPC lets you define API procedures on the server and call...
TSConfig
The `tsconfig.json` configuration file at the root of a TypeScript project that specifies compiler options (target, module system, strictness level), file...
Type Alias
A named shorthand for an existing type or type expression, introduced with `type` in TypeScript or `typedef`/`using` in other languages. It does not create a...
Type Annotation
An explicit label attached to a variable, parameter, or return value that declares its expected type — such as `let count: number` in TypeScript or `def...
Type Assertion
A compile-time directive that tells the type checker to treat a value as a specific type, bypassing inference — written as `value as Type` in TypeScript or...
Type Declaration
A statement that introduces a new named type into the type system — such as an `interface`, `type`, `class`, or `enum` in TypeScript, or a `struct`/`enum` in...
Type Definition
A file (typically `.d.ts` in TypeScript) that describes the types, interfaces, and function signatures of a module without containing executable code. The...
Type Guard
A runtime check that narrows the type of a variable within a conditional block. In TypeScript, type guards use typeof, instanceof, or custom predicates to tell...
Type Narrowing
A type system feature where the compiler refines a variable's type to a more specific one within a conditional branch — for example, after an `if (typeof x ===...
TypeORM
An ORM for TypeScript and JavaScript that maps database tables to classes using decorators, supporting both Active Record and Data Mapper patterns across...
Type Predicate
A special return type annotation in TypeScript of the form `param is Type` that tells the compiler a boolean-returning function acts as a type guard — if the...
TypeScript Compiler
The official TypeScript compiler (`tsc`), written in TypeScript itself, that parses `.ts`/`.tsx` files, performs static type checking against the project's...
Type Widening
A behavior in TypeScript's type inference where a literal type is automatically broadened to its base type — for example, a `let` variable initialized with...
Union
In type systems, a union type represents a value that can be one of several types — written as `string | number` in TypeScript, meaning the value is either a...
Union Type
A type that represents a value which can be one of several specified types. Written as A | B in TypeScript, the compiler ensures you handle all possible...
Utility Type
A built-in generic type in TypeScript that transforms other types — for example, Partial<T> makes all properties optional, Pick<T, K> selects a subset of...
Utility Types
Built-in generic types in TypeScript (Partial, Required, Pick, Omit, Record, etc.) that transform existing types. They reduce boilerplate by deriving new types...
Zod
A TypeScript-first schema declaration and validation library that lets developers define a schema once and automatically infer the corresponding TypeScript...

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