TypeScript snippets

14 snippets

• TypeScript Tested

  Typed Object.keys and Object.entries

  Helpers that keep key types instead of widening to string, for objects you know the shape of.

• TypeScript Tested

  Type-safe event emitter

  An event emitter whose event names and payloads are checked by the compiler through a generic map type.

• TypeScript Tested

  Check an object against a type with satisfies

  Validate a config object against an interface while keeping its precise literal types.

• TypeScript Tested

  Parse JSON into a typed value with a guard

  Safely turn unknown JSON into a typed result by validating its shape instead of casting.

• TypeScript Tested

  Non-empty array type

  Encode "at least one element" in the type so head, max and similar functions never see an empty array.

• TypeScript Tested

  Generic groupBy with key inference

  Group an array into a Record by a property or function while keeping the item type.

• TypeScript Tested

  Typed fetch helper that checks the response

  A fetch wrapper that throws on HTTP errors and validates the JSON body with a type guard.

• TypeScript Tested

  Debounce with preserved argument types

  A debounce function whose returned function keeps the parameter types and exposes cancel() and flush().

• TypeScript Tested

  Branded types for IDs

  Prevent mixing up UserId and OrderId strings by giving each a unique compile-time brand.

• TypeScript Tested

  Assert a value is not null or undefined

  An assertion function that narrows away null and undefined and throws a clear error otherwise.

• TypeScript Tested

  Type-safe pick and omit helpers for objects

  Copy selected keys from an object (or drop some) with return types that match at compile time.

• TypeScript Tested

  A typed Result type for error handling without exceptions

  Model success and failure as a discriminated union so callers must handle both cases.