RegExp.ts

RegExp.ts overview

Tools for working with JavaScript regular expressions from the Effect module namespace. The module exposes the native RegExp constructor, a guard for narrowing unknown values, and escaping for literal text that will be embedded in a pattern.

Reach for RegExp when you need to build a regular expression from user or data-driven text, check whether an unknown value is already a RegExp, or access the native constructor without leaving the Effect namespace.

Since v2.0.0

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Exports Grouped by Category

• RegExp
  • escape
• constructors
  • RegExp
• guards
  • isRegExp

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RegExp

escape

Escapes special characters in a regular expression pattern.

When to use

Use to turn literal text into a safe regular expression pattern fragment.

Example (Escaping a pattern string)

import { RegExp } from "effect"
import * as assert from "node:assert"

assert.deepStrictEqual(RegExp.escape("a*b"), "a\\*b")

Signature

declare const escape: (string: string) => string

Source

Since v2.0.0

constructors

RegExp

Exposes the JavaScript regular expression constructor from globalThis.

When to use

Use to construct JavaScript regular expressions through the Effect module namespace.

Example (Creating a regular expression)

import { RegExp } from "effect"

// Create a regular expression using Effect's RegExp constructor
const pattern = new RegExp.RegExp("hello", "i")

// Test the pattern
console.log(pattern.test("Hello World")) // true
console.log(pattern.test("goodbye")) // false

Signature

declare const RegExp: RegExpConstructor

Source

Since v4.0.0

guards

isRegExp

Checks whether a value is a RegExp.

When to use

Use to validate unknown input before treating it as a regular expression.

Example (Checking for regular expressions)

import { RegExp } from "effect"
import * as assert from "node:assert"

assert.deepStrictEqual(RegExp.isRegExp(/a/), true)
assert.deepStrictEqual(RegExp.isRegExp("a"), false)

Signature

declare const isRegExp: (input: unknown) => input is RegExp

Source

Since v3.9.0