escapeSpecialRegexCharacters

The escapeSpecialRegexCharacters function escapes special regex characters in a string, making it safe to use in a regular expression.

Basic Usage

import { escapeSpecialRegexCharacters } from "cx/util";

escapeSpecialRegexCharacters("hello.world");
// "hello\\.world"

escapeSpecialRegexCharacters("price: $100");
// "price: \\$100"

escapeSpecialRegexCharacters("[test]");
// "\\[test\\]"

Escaped Characters

The following characters are escaped: \ ^ $ * + ? . ( ) | [ ] { }

import { escapeSpecialRegexCharacters } from "cx/util";

escapeSpecialRegexCharacters("a.b");    // "a\\.b"
escapeSpecialRegexCharacters("a*b");    // "a\\*b"
escapeSpecialRegexCharacters("a+b");    // "a\\+b"
escapeSpecialRegexCharacters("a?b");    // "a\\?b"
escapeSpecialRegexCharacters("a|b");    // "a\\|b"
escapeSpecialRegexCharacters("(a)");    // "\\(a\\)"
escapeSpecialRegexCharacters("[a]");    // "\\[a\\]"
escapeSpecialRegexCharacters("{a}");    // "\\{a\\}"
escapeSpecialRegexCharacters("^a$");    // "\\^a\\$"
escapeSpecialRegexCharacters("a\\b");   // "a\\\\b"

Common Use Cases

Safe Search Patterns

import { escapeSpecialRegexCharacters } from "cx/util";

function createSearchRegex(userInput: string): RegExp {
  const escaped = escapeSpecialRegexCharacters(userInput);
  return new RegExp(escaped, "gi");
}

// User searches for "C++" - without escaping, + is a quantifier
const regex = createSearchRegex("C++");
regex.test("Learn C++ programming"); // true

Dynamic Pattern Building

import { escapeSpecialRegexCharacters } from "cx/util";

function highlightText(text: string, searchTerm: string): string {
  const escaped = escapeSpecialRegexCharacters(searchTerm);
  const regex = new RegExp(`(${escaped})`, "gi");
  return text.replace(regex, "<mark>$1</mark>");
}

highlightText("File: test.txt", "test.txt");
// "File: <mark>test.txt</mark>"

Filter with Literal Match

import { escapeSpecialRegexCharacters } from "cx/util";

function filterByExactSubstring(items: string[], search: string): string[] {
  const escaped = escapeSpecialRegexCharacters(search);
  const regex = new RegExp(escaped, "i");
  return items.filter((item) => regex.test(item));
}

const files = ["config.json", "data.json", "test[1].json"];
filterByExactSubstring(files, "[1]");
// ["test[1].json"]

API

function escapeSpecialRegexCharacters(s: string): string;

Returns: The input string with all regex special characters escaped.

See Also

• getSearchQueryPredicate - Uses this internally for safe search matching