Package Exports

handy-ts-tools
handy-ts-tools/asserts
handy-ts-tools/helpers
handy-ts-tools/helpers/async-iterable
handy-ts-tools/helpers/core
handy-ts-tools/helpers/enum
handy-ts-tools/helpers/error
handy-ts-tools/helpers/iterable
handy-ts-tools/helpers/number
handy-ts-tools/helpers/object
handy-ts-tools/helpers/promise
handy-ts-tools/helpers/string
handy-ts-tools/package.json
handy-ts-tools/typeguards
handy-ts-tools/types

Readme

handy-ts-tools

Small TypeScript-first toolkit with no runtime dependencies. Everything is grouped by intent so it is easy to tree-shake only what you need:

typeguards — runtime guards for narrowing values;
asserts — lightweight assertions and custom error types;
helpers — utility functions split by domain (core, iterable, asyncIterable, object, string, number, promise, error, enum);
types — pure TypeScript helpers like ValueOf, RequireAtLeastOne, and DeepReadonly.

Usage

import { assertDefined, ensureSuffix, pipe, toPercent } from "handy-ts-tools";
import { isNonEmptyArray, mapAsyncIterable } from "handy-ts-tools/typeguards";
import { take, toArray } from "handy-ts-tools/helpers/iterable";
import { toArrayAsync } from "handy-ts-tools/helpers/async-iterable";

const payload = assertDefined(maybeValue, "payload must be loaded");
const completedPercent = toPercent(payload.completed, payload.total);
const listTitle = ensureSuffix(payload.name, ":");

if (isNonEmptyArray(payload.items)) {
  const firstThree = toArray(take(payload.items, 3));
  console.log(listTitle, firstThree);
}

const asyncStream = mapAsyncIterable(payload.asyncItems, (item) => ({ ...item, hydrated: true }));
const buffered = await toArrayAsync(asyncStream);
console.log("ready", buffered, completedPercent);

Type helper example

import type { RequireAtLeastOne } from "handy-ts-tools/types";

type FetchOptions = RequireAtLeastOne<
  {
    userId?: string;
    email?: string;
    phone?: string;
  },
  "userId" | "email" | "phone"
>;

// ✅ at least one identifier is required
const request: FetchOptions = { email: "user@example.com" };

Available helpers

Category	Functions
`typeguards`	`isDefined`, `isString`, `isNumber`, `isPlainObject`, `isNonEmptyArray`, `isOneOf`, `isDiscriminatedUnionMember`
`asserts`	`AssertionError`, `assert`, `assertDefined`, `assertNever`
`helpers/core`	`identity`, `noop`, `pipe`, `clamp`
`helpers/object`	`pick`
`helpers/promise`	`createDeferred`
`helpers/iterable`	`toArray`, `mapIterable`, `filterIterable`, `take`, `drop`, `flatMapIterable`, `reduceIterable`
`helpers/asyncIterable`	`toArrayAsync`, `mapAsyncIterable`, `filterAsyncIterable`, `takeAsync`, `reduceAsyncIterable`
`helpers/string`	`ensurePrefix`, `ensureSuffix`, `capitalize`, `truncate`
`helpers/number`	`roundTo`, `inRange`, `toPercent`
`helpers/error`	`isErrorLike`, `wrapError`, `retry`
`helpers/enum`	`parseEnumValue`
`types`	`ValueOf`, `RequireAtLeastOne`, `DeepReadonly`, `Exact`, `UnionToIntersection`

Development

pnpm install       # install dependencies
pnpm run build     # emit dist/ artifacts
pnpm test          # run Vitest suite

Build uses tsc; tests are handled by Vitest. pnpm is the default package manager for this repo, but npm/yarn work too.

Selective imports

Every module is exposed via explicit subpaths to keep bundles small:

import { assert } from "handy-ts-tools/asserts";
import { ensurePrefix } from "handy-ts-tools/helpers/string";
import { isDiscriminatedUnionMember } from "handy-ts-tools/typeguards";

Changelog & License

See CHANGELOG.md for release notes; update the date before publishing a new version.
Distributed under the MIT license.