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helpers4 helpers4

Helpers 4 TypeScript

Production-ready TypeScript utility functions — modular, strictly typed, exhaustively tested.

Section titled “Quick Links”

What is helpers4?

Section titled “What is helpers4?”

A collection of functional helpers to stop rewriting the same utility code across every project — each function does one thing, does it right, and ships with full type safety and exhaustive tests.

Born from 10 years of recoding the same domain-specific helpers across projects, helpers4 covers the gaps that popular general-purpose toolkits deliberately exclude: dates, URLs, semver, observables, promise guards. The Philosophy and the Radashi comparison pages explain the reasoning in detail.

  • ✅ Tree-shakable — import one function, pay for one function
  • ✅ Framework-agnostic — React, Vue, Svelte, Angular, or no framework at all
  • ✅ Well-typed — strict TypeScript, no any, full inference
  • ✅ Zero runtime dependencies — nothing pulled in at runtime
  • ✅ Battle-tested — 100% coverage, >90% mutation score, property-based · contract · boundary · security tests
  • ✅ Enterprise-grade — formal LGPL-3.0 license, audit-ready, predictable at scale
  • ✅ AI-ready — exhaustive contracts make every function safe to call from generated or agentic code

What’s new in V3?

Section titled “What’s new in V3?”

V3 is a cleanup-and-growth release: two categories reorganized for clarity, 25+ new helpers, zero logic changes for anyone using the replacements below.

⚠️ Breaking: type → guardRuntime type guards (isString, isArray, isDefined, …) moved to a new @helpers4/guard package; @helpers4/type now only holds compile-time-only utility types. See the migration guide
⚠️ Breaking: 6 removed aliasesdeepMerge/deepClone/daysDifference/safeDate/dateToISOString/type.isEmpty — all had a direct replacement since v1.9.0/v2.0.0, see the migration guide for the full table
New color categoryhexToRgb, rgbToHex, hslToRgb, rgbToHsl, argbToRgb, plus isCssColor in guard
25+ new helpersclone, flatten/unflatten, pickBy/omitBy/unset/update, parsePropertyPath, replaceOrAppend, toggle, symmetricDifference, dedent, removeDiacritics, unescapeHtml, escapeRegExp, parseDuration, unary, isWeakMap/isWeakSet/isSet, and more
Mutation testing>90% score — tests verified to catch regressions, not just execute — dashboard
Property-based testsInvariants validated against thousands of random inputs (fast-check)
Contract testsFormal behavioral guarantees for each function
Boundary & security testsEdge values and security-sensitive inputs (prototype pollution, injections)
Native API trackingStandard JS equivalents documented, not re-implemented

Comparisons

Section titled “Comparisons”

Wondering how helpers4 stacks up against other utility libraries? See the comparisons section.

Name conflicts between categories

Section titled “Name conflicts between categories”

Some helpers share the same name across multiple categories — for example, compact exists in both @helpers4/array and @helpers4/object because it is a genuinely different operation on a different data type. When you need both in the same file, use the standard ES module as rename:

import { compact as compact4array } from '@helpers4/array';
import { compact as compact4object } from '@helpers4/object';

See the full list in Name Conflicts.

Contributing

Section titled “Contributing”

Found a bug or want to suggest a helper? Open an issue on the TypeScript repository.

Want to improve this documentation? Use the Edit page link at the bottom of any page, or open an issue on the website repository.