tsdef

library0.0.14jsnpmunverified

tsdef is a TypeScript utility library that provides a curated collection of common type definitions and aliases to simplify complex type patterns and enhance code readability in TypeScript projects. It aims to reduce boilerplate and improve type safety by offering widely applicable utility types such as `Nullable`, `NonNull`, `MaybePromise`, and various `Props` modifiers (e.g., `NonNullProps`, `WritableProps`). The current stable version is 0.0.14. As a pre-1.0 release, its release cadence is likely irregular, and breaking changes might occur more frequently than with a semantically versioned stable library. It differentiates itself by being a pure type-only library, meaning it introduces zero runtime overhead and focuses exclusively on type-system improvements, making it suitable for projects that prioritize strict type integrity without adding to the JavaScript bundle size.

type-stubs

npm install tsdef

github ↗package ↗

INSTALL

IMPORT

SIG · TSDEF

tsdef

type-stubsjavascriptv0.0.14

Install

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Import

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Disk

—

Pass rate

0/ 6

Env Coverage0 / 6

glibc

18–22

musl

18–22

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–226 runs

build_error

glibc

node 18–226 runs

build_error

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

Nullable

✓ import { Nullable } from 'tsdef';

✗ const Nullable = require('tsdef').Nullable;

tsdef exports only TypeScript types, not runtime values. CommonJS 'require' syntax for types is incorrect and will result in a runtime error or a TypeScript error depending on compiler settings.

NonNull

✓ import { NonNull } from 'tsdef';

✗ import NonNull from 'tsdef';

All exports from tsdef are named exports; there is no default export. Incorrectly attempting a default import will result in a TypeScript error.

AnyFunction

✓ import { AnyFunction } from 'tsdef';

This type alias helps define variables that are expected to be any kind of function, improving clarity and type safety for function parameters or return types.

This quickstart demonstrates the usage of `Nullable`, `NonNull`, `MaybePromise`, and `MaybeArray` type utilities from `tsdef` to handle common TypeScript type patterns, showcasing how to define types that explicitly allow or disallow null/undefined, or encapsulate potential promises or arrays.

import { Nullable, NonNull, MaybePromise, MaybeArray } from 'tsdef'; // Define a string that can also be null or undefined const nullableString: Nullable<string> = 'hello'; const anotherNullableString: Nullable<string> = null; // This is OK // const invalidNullableString: Nullable<string> = undefined; // Also OK if 'nil' includes undefined // Define a string that explicitly cannot be null const nonNullString: NonNull<string | null> = 'world'; // const invalidNonNullString: NonNull<string | null> = null; // Type error: Type 'null' is not assignable to type 'string'. // Define a value that might be a promise or the value itself type User = { id: string; name: string }; const getUserSync = (): User => ({ id: '1', name: 'Alice' }); const getUserAsync = (): Promise<User> => Promise.resolve({ id: '2', name: 'Bob' }); const maybePromiseUser: MaybePromise<User> = getUserSync(); const anotherMaybePromiseUser: MaybePromise<User> = getUserAsync(); // Define a value that might be a single item or an array of items const singleItem: MaybeArray<string> = 'item'; const multipleItems: MaybeArray<string> = ['item1', 'item2']; console.log(nullableString); // Output: hello console.log(nonNullString); // Output: world

Debug

Known issues

gotchatsdef is currently at version 0.0.14, indicating it is in a pre-1.0 development phase. This means that semantic versioning might not be strictly adhered to, and breaking changes could be introduced in minor or even patch releases without explicit major version bumps. Users should review changelogs carefully when upgrading.

fix

Pin the exact version of `tsdef` in your `package.json` (e.g., `"tsdef": "0.0.14"`) and manually review release notes before updating to new versions, especially for critical production applications.

affects: >=0.0.1

gotchaAs a purely type-definition library, `tsdef` should always be installed as a development dependency (`-D` or `--save-dev`) as it produces no runtime code. Installing it as a regular dependency (`-S` or `--save`) will needlessly add it to your production bundle's dependency tree, although it won't increase the actual runtime bundle size.

fix

Ensure installation with `npm install -D tsdef` or `yarn add -D tsdef`. If already installed incorrectly, move it from `dependencies` to `devDependencies` in `package.json`.

affects: >=0.0.1

gotchaThe extensive set of utility types provided by `tsdef` (and similar libraries like `ts-essentials` or `type-fest`) can sometimes lead to naming conflicts or overlap with built-in TypeScript utility types or those from other libraries if not managed carefully.

fix

Be mindful of potential naming collisions. If a conflict occurs, consider importing with an alias (e.g., `import { Nullable as TsdefNullable } from 'tsdef';`) or evaluating if a native TypeScript utility type serves the same purpose.

affects: >=0.0.1

Errors

Common errors & fixes

Cannot find module 'tsdef' or its corresponding type declarations.

The `tsdef` package was either not installed, installed incorrectly, or TypeScript is not configured to find type declaration files.

fix

Ensure `tsdef` is installed as a dev dependency: `npm install -D tsdef` or `yarn add -D tsdef`. Also, verify your `tsconfig.json` includes `"typeRoots": ["./node_modules/@types", "./node_modules"]` or similar settings to allow TypeScript to discover type declarations.

Type 'null' is not assignable to type 'NonNull<string>'.

Attempting to assign `null` (or `undefined` for `NonNil`) to a type that explicitly removes `null` (or `nil`) from its possible values. This is a correct type error, indicating a violation of the `NonNull` (or `NonNil`) constraint.

fix

Refactor your code to ensure that values assigned to `NonNull` types are indeed guaranteed to be non-null. This often involves null checks (`if (value !== null)`) or using optional chaining (`?.`) and nullish coalescing (`??`) operators before assignment or usage.

Property 'someProperty' does not exist on type 'NonNilProps<MyType>'.

When applying `NonNilProps` (or `NonNullProps`, `NonUndefinedProps`), if the original type `MyType` had optional properties, these `Props` utility types do not automatically make them required. They only ensure that *if* a property exists, its value is non-nil/non-null/non-undefined.

fix

If you intend for properties to be required *and* non-nil, combine `NonNilProps<T>` with `RequiredProps<T>` or directly use `Required<NonNilProps<T>>` to achieve the desired strictness.

Upgrade

Version history

0.0.14latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

32 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/joonhocho/tsdef ↗

packagehttps://www.npmjs.com/package/tsdef ↗