oh-my-regex

Readable string validation without writing regex — chainable predicate API.

Install

npm i oh-my-regex

Quick start

import { regex } from "oh-my-regex";

regex("123cose98").hasNumber().hasLetter().ok(); // true
regex("ab").hasNumber().hasUppercase().ok();      // false

API (includes semantics)

All checks use includes semantics: "does the string contain somewhere (or satisfy) this condition?". There is no full-string match in this API.

| Method | Example | |--------|---------| | hasNumber() | regex("x1").hasNumber().ok() | | hasLetter() | regex("1a").hasLetter().ok() | | hasUppercase() / hasLowercase() | regex("Ab").hasUppercase().ok() | | hasLanguage("ko") | regex("한글").hasLanguage("ko").ok() (MVP: "ko" only) | | hasSymbol() | regex("a@").hasSymbol().ok() | | minLength(n) / maxLength(n) | regex("abc").minLength(3).ok() | | startsWith(needle) / endsWith(needle) / includes(needle) | regex("hello").includes("ell").ok() | | raw(re) | regex("123").raw(/\d{3}/).ok() (options like caseInsensitive do not apply) | | caseInsensitive() | regex("ABC").caseInsensitive().hasLetter().ok() |

End with:

• ok() or test() — true if all conditions pass (AND).
• report() — { ok, failed: [{ name, message? }], passed: string[] }.
• explain() — human-readable summary of what passed/failed.
• build(options?) — returns the combined RegExp from combinable predicates, or null when there are none. Options: { global?: boolean } to add the g flag. Use .source on the result for the pattern string.

report() example

const r = regex("ab").hasNumber().hasUppercase().report();
// { ok: false, failed: [{ name: "hasNumber" }, { name: "hasUppercase" }], passed: [] }

explain() example

regex("a").hasNumber().hasLetter().explain();
// "Failed: hasNumber. Passed: hasLetter"

build() example

const re = regex("x").hasNumber().hasLetter().build();
// RegExp from combinable predicates; re.test("a1") === true

regex("x").build();                    // null (no combinable predicates)
regex("a1").hasNumber().build({ global: true });  // RegExp with "g" flag

Notes

• Includes semantics: Only "somewhere" / substring-style checks. No "whole string must match" in this API.
• raw(re): Uses your RegExp as-is; caseInsensitive() and other options do not apply. Multiple raw() predicates are distinguished in report().failed by a short pattern snippet in name (e.g. raw(/\d/)). Avoid patterns that cause catastrophic backtracking (e.g. nested quantifiers on overlapping alternations); raw() runs your RegExp as-is and can block the main thread.
• hasLetter(): Latin letters only (A–Z, a–z). For other scripts use hasLanguage(locale) (e.g. hasLanguage("ko") for Hangul).
• hasLanguage(locale): MVP supports only "ko". Unsupported locale (e.g. "en", "ja"): always false, no error.
• hasSymbol(): At least one character that is not whitespace, digit, A–Z, a–z, or Hangul (가–힣). Non-ASCII scripts (Japanese, Chinese, Arabic, etc.) are treated as symbols in MVP; in i18n contexts, "symbol" here includes non-Latin scripts.
• startsWith(re) / endsWith(re): When needle is a RegExp, a ^ or $ anchor is added automatically if not already present. caseInsensitive() does not apply to RegExp needles — set the i flag directly (e.g. /hel/i).
• minLength(n) / maxLength(n): Throws when the predicate is created (at chain build time) if n is negative or non-integer (fail-fast).

License

MIT