markwhitaker/RegexToolbox.js

Regular expression tools for JavaScript developers.

npm i regextoolbox

RegexBuilder is a class for building regular expressions in a more human-readable way using a fluent API. It offers a number of benefits over using raw regex syntax in strings:

• No knowledge of regular expression syntax is required: just use simple, intuitively-named classes and methods.
• Code is easier to read, understand and maintain.
• Code is safer and far less prone to regular expression syntax errors and programmer errors.

It is fully documented in the project wiki.

The grouping methods have been totally overhauled in version 2.0 to make them easier to use and less error-prone.

Go from this:

const regex = new RegexBuilder()
    .startGroup()
    .digit()
    .letter()
    .buildRegex(); // ERROR: forgot to call endGroup()

To this:

const regex = new RegexBuilder()
    .group(r => r
        .digit()
        .letter()
    )
    .buildRegex();

Details of breaking changes:

Go from this:

RegexQuantifier.oneOrMore.butAsFewAsPossible()

to this:

RegexQuantifier.oneOrMore.butAsFewAsPossible

Support for named groups has been added. Where the captured values for regular groups are retrieved like this:

const regex = new RegexBuilder()
    .group(r => r
        .uppercaseLetter()
    )
    .lowercaseLetter(RegexQuantifier.oneOrMore)
    .buildRegex();

const initial = regex.exec("Mark")[1]; // "M"

the captured values for named groups are retrieved like this:

// Get a number using a group of digits
const regex = new RegexBuilder()
    .namedGroup("initialLetter", r => r
        .uppercaseLetter()
    )
    .lowercaseLetter(RegexQuantifier.oneOrMore)
    .buildRegex();

const initial = regex.exec(input).groups.initialLetter; // "M"

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