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.

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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

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Installation

npm install easy-regex-ts

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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+"

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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();

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Type Safety

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

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

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License

MIT