REGEX BLOCKS

Programatically build, edit, and compile regular expressions, one block at a time.

npm i -S regex-blocks

List of Operations

All operations can be chained together. Use regex(...operations).compile() to generate the RegExp object.

Character Classes

• strings regex(str('my string')) // => my string
• any character regex(anything()) // => .
• word regex(word()) => // => \w
• digit regex(digit()) // => \d
• space regex(space()) // => \s
• character sets regex(inSet( string )) // => [abc]
• not in sets regex(inSet( string ).not()) // => [^abc]

Anchors

• start of string regex(str('abc')).startsWith() // => ^abc
• end of string regex(str('abc')).endsWith() // => abc$
• both regex(str('abc')).fullMatch() // => ^abc$

Groups and Lookaround

• capture groups regex(str('abc').capture()); // => (abc)
• non-capturing groups regex(group(str('a'), str('b'), str('c'))); // => (?:abc)
• lookahead regex(str('abc').whenFollowedBy(str('def'))) // => abc(?=def)
• back-references regex(inSet(str('a'), str('b')).capture(), str('--'), backRef(1)) // => ([ab])--\1
• lookbehind regex(str('def').whenFollowing(str('abc'))) // => (?!abc)def

Quantifiers

• kleene star regex( word().zeroOrMore() ) // => \w*
• kleene plus regex( word().oneOrMore() ) // => \w+
• repetitions regex( word().repeat(2, 3) ) // => \w{2,3}

Alternations

• or regex( any( str('a'), str('b'), str('c') ) ) // => (?:a|b|c)

Examples

Valid Email Regex

let regexp = regex(
    word().oneOrMore(),
    str('@'),
    word().oneOrMore(),
    any(
        str('.com'),
        str('.io'),
        str('.org')
    )
).fullMatch().compile();
// => /^$\w+@\w+(?:\.com|\.io|\.org)/