easy-regex-ts

Fluent, type-safe regex builder for TypeScript

easy-regex-ts is a zero-dependency, fully type-safe regex builder. It provides a fluent API for building complex regular expressions with full TypeScript inference, runtime safety, and modern regex features like lookaheads, alternation, and quantifiers.

Features

• Full type inference – see the exact pattern in your IDE
• Fluent API – chain methods like .digit().maybe()
• Runtime safety – invalid usage throws clear errors
• Zero dependencies – pure TypeScript
• Supports modern regex features – lookaheads, alternation, quantifiers

Installation

npm install easy-regex-ts

API Reference

Building Blocks

Building Blocks

| Method | Example | Output | |--------|--------|--------| | .start() / .end() | regex().start().digit().end() | ^\d$ | | .digit() | regex().digit().repeat(2) | \d{2} | | .word() | regex().word() | \w+ | | .any() | regex().any().repeat(3) | .{3} | | .letter() | regex().letter() | [a-zA-Z] | | .space() | regex().space().zeroOrMore() | * | | .tab() | regex().tab() | \t | | .wordBoundary() | regex().wordBoundary() | \b | | .literal(str) | regex().literal('https://') | https:\/\/ | | .anyOf(chars) | regex().anyOf('a-f0-9') | [a-f0-9] | | .noneOf(chars) | regex().noneOf(' <>') | [^ <>] | | .maybe() | regex().digit().maybe() | \d? | | .oneOrMore() | regex().digit().oneOrMore() | \d+ | | .zeroOrMore() | regex().space().zeroOrMore() | * | | .repeat(n) | regex().digit().repeat(3) | \d{3} | | .between(min,max) | regex().anyOf('_').between(3,15) | [_]{3,15} | | .atLeast(n) | regex().any().atLeast(8) | .{8,} | | .or(r => ...) | regex().literal('cat').or(r => r.literal('dog')) | (cat\|dog) | | .group(r => ...) | regex().group(r => r.digit().literal('-')) | (\d-) | | .lookahead(str) | regex().lookahead('(?=.*[A-Z])') | (?=.*[A-Z]) |

Terminal Methods

const r = regex().digit().oneOrMore();

// Convert to RegExp
r.toRegExp('g');   // /\d+/g

// Get string pattern
r.toString();      // "\d+"

// Test a string
r.test('123');     // true

// Access typed pattern
r.pattern;         // "\d+"

Examples

Password (8+ chars, 1 uppercase, 1 digit)

const password = regex()
  .start()
  .lookahead('(?=.*[A-Z])')
  .lookahead('(?=.*\\d)')
  .any().atLeast(8)
  .end();

Twitter Handle

const handle = regex()
  .start()
  .literal('@')
  .anyOf('a-zA-Z0-9_').between(3, 15)
  .end();

Type Safety

const slug = regex()
  .start()
  .letters(1)
  .word().zeroOrMore()
  .literal('-')
  .word()
  .end();

// Hover over `slug.pattern` → "^[a-zA-Z]\w*-\w+$"

License

MIT