Registry / serialization / type-level-regexp

type-level-regexp

library0.1.17jsnpmunverified

Type-Level RegExp (current version 0.1.17) is a TypeScript library that implements a regular expression parser and matcher entirely at the type level, leveraging TypeScript's template literal types. It allows developers to define regex patterns as string literals and receive compile-time type-safe results when using `String.match()`, `String.matchAll()`, and `String.replace()`. This provides robust validation of regex syntax and strongly typed access to capture groups, significantly reducing runtime errors related to incorrect regex patterns or mismatched group access. The library is currently under active development ('Work In Progress'), implying an iterative release cadence focused on feature expansion and refinement. Its primary differentiator is the deep integration of regex parsing into the TypeScript type system, offering static analysis benefits not typically found in runtime-only regex solutions.

serialization

npm install type-level-regexp

github ↗package ↗

INSTALL

IMPORT

SIG · TYPE-LEVEL-REGEXP

type-level-regexp

serializationjavascriptv0.1.17

Install

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Import

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Disk

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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.

createRegExp

✓ import { createRegExp } from 'type-level-regexp'

✗ const createRegExp = require('type-level-regexp')

Primary function to create a typed RegExp object. Uses ESM imports.

spreadRegExpIterator

✓ import { spreadRegExpIterator } from 'type-level-regexp'

✗ const spreadRegExpIterator = require('type-level-regexp').spreadRegExpIterator

Utility function for converting the iterator returned by `String.matchAll()` into a typed array.

ParseRegExp

✓ import { ParseRegExp } from 'type-level-regexp'

Type-level utility for parsing a RegExp string into its abstract syntax tree (AST). Imported as a type, not a runtime value.

MatchRegExp

✓ import { MatchRegExp } from 'type-level-regexp'

Type-level utility for matching a string against a parsed RegExp AST. Imported as a type, not a runtime value.

Demonstrates how to use `createRegExp` to get strongly typed match results for `String.match()`, `String.replace()`, and `String.matchAll()` against literal strings, including access to capture groups and iterator spreading.

import { createRegExp, spreadRegExpIterator } from 'type-level-regexp' /** string.match() */ const regExp = createRegExp('foO(?<g1>b[a-g]r)(?:BAz|(?<g2>qux))', ['i']) const matchResult = 'prefix foobarbaz suffix'.match(regExp) // matching literal string if (matchResult) { console.log(matchResult[0]) // 'foobarbaz' console.log(matchResult[1]) // 'bar' // matchResult[3] // TypeScript error: type '3' can't be used to index type 'RegExpMatchResult<...>' (as shown in README) console.log(matchResult.length) // 3 console.log(matchResult.index) // 7 console.log(matchResult.groups) // { g1: "bar"; g2: undefined; } } /** string.replace() */ const regExp2 = createRegExp('(\\d{4})[-.](?<month>\\w{3,4})[-.](?:\\d{1,2})') const replaceResult = '1991-Sept-15'.replace(regExp2, '$<month> $3, $1') console.log(replaceResult) // 'Sept 15, 1991' /** string.matchAll() */ const regExp3 = createRegExp('c[a-z]{2}', ['g']) const matchALlIterator = 'cat car caw cay caw cay'.matchAll(regExp3) const spreadedResult = spreadRegExpIterator(matchALlIterator) console.log(spreadedResult[2][0]) // 'caw' console.log(spreadedResult[3]?.index) // 12

Debug

Known issues

gotchaThe library is explicitly marked as 'Work In Progress' (WIP), meaning that APIs and internal implementations are subject to change without strict adherence to semantic versioning for minor updates. Users should expect potential breaking changes in minor or patch releases until a stable major version is released.

fix

Monitor the GitHub repository for updates and review release notes carefully before upgrading. Pin exact versions for production use and consider using the TypeScript Playground link to test changes.

affects: >=0.1.0

gotchaWhen matching against dynamic (non-literal) strings, the type-level matcher will provide enumerated or less precise types for match results, as the exact match structure cannot be determined at compile-time. Full type-level precision is primarily available when matching against string literals.

fix

For dynamic string matching, validate runtime results if strict typing is critical, or consider using runtime assertions. If possible, refactor to use literal strings where type-level guarantees are most valuable.

affects: >=0.1.0

breakingSupplying an invalid regular expression pattern to `createRegExp` will result in a TypeScript compilation error, preventing the code from compiling. This is a deliberate design choice to enforce regex correctness at compile-time, unlike runtime regex engines that would throw a runtime error.

fix

Ensure all regular expression patterns passed to `createRegExp` are syntactically valid and correctly formed according to JavaScript RegExp syntax. Utilize online regex testers or the provided TypeScript Playground link for validation during development.

affects: >=0.1.0

Errors

Common errors & fixes

Argument of type 'string' is not assignable to parameter of type 'RegExpSyntaxError<"Invalid regular expression, missing closing `)`">'

An invalid regular expression string was passed to the `createRegExp` function.

fix

Correct the regular expression string to be syntactically valid (e.g., ensure all opening parentheses have a matching closing parenthesis).

Upgrade

Version history

0.1.17latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

23 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/didavid61202/type-level-regexp ↗

packagehttps://www.npmjs.com/package/type-level-regexp ↗