regex-repo

A a collection of useful regular expressions. Refer to the regex reference below for a list of the provided REs. Supports both CJS and ESM packages.

Installation

npm i @liquid-labs/regex-repo

pnpm and yarn also work.

Usage

import { emailRe } from '@liquid-labs/regex-repo' // ES6
// const { emailRe } = require('@liquid-labs/regex-repo') // cjs

const verified = emailRe.test(userInput)

Regex reference

Each regular expression listed below is paired with an embeddable string named xxxString. E.g., rgbRe is paired with rgbReString (special cases noted). Each Re will only match strings that are the given type and nothing else. I.e., the RE begins with '^' and ends with '$'. The xxxReString can be used for partial matches, matchAlls, and used as part of larger expressions. E.g., to find all unique CSS RGB colors used in a style sheet, you might do something like:

import { rgbReString } from '@liquid-labs/regex-repo'

const allColors = cssContent
  .matchAll(new RegExp(`[ :](${rgbReString})[; }]`, 'g'))
  .map((match) => match[1]) // extract the capture group
  .filter((v, i, arr) => i === arr.indexOf(v)) // filter non-unique items
  .sort()

API generated with dmd-readme-api.

• Constants:
  • AWS
    • awsS3BucketNameRe: Matches (most) valid S3 bucket name.
    • awsS3BucketNameReString: An RE ready string that matches (most) valid S3 bucket names.
    • awsS3TaBucketNameRe: Matches (most) S3 Transfer Acceleration compatible S3 bucket name.
    • awsS3TaBucketNameReString: An RE ready string that matches (most) valid S3 Transfer Acceleration compatible bucket names.
    • invalidS3TaBucketNameReString: An RE ready string that matches excluded S3 Transfer Acceleration compatible bucket names that would be matched by awsS3TaBucketNameReString.
  • Contacts
    • emailRe: Match most valid emails.
    • usPhoneRe: Matches US phone numbers with optional country code and area code.
    • zipCodeRe: Matches 5 or 9 digit US zip codes.
  • CSS
    • cssColor3Re: Matches CSS3 'hex, rgb, rgba, hsl, and predefined colors.
    • cssColorRe: Matches CSS4 'hex, rgb, rgba, hsl, and predefined colors.
    • cssPreColors1Re: Matches CSS1 predefined color names.
    • cssPreColors2Re: Matches CSS2 predefined color names.
    • cssPreColors3Re: Matches CSS3 predefined color names.
    • cssPreColorsRe: Matches CSS4 predefined color names.
    • hexColorAlphaRe: Matches hex specified RGBA colors with an alpha channel.
    • hexColorNoAlphaRe: Matches hex specified RGB colors with no alpha channel.
    • hsl3Re: Matches CSS3 'hsl(...) and hsla(...) deg and percent notation.
    • hslRe: Matches CSS4 'hsl(...) and hsla(...) deg, grad, rad, turn and percent notation.
    • rgbaFuncRe: Matches CSS3 'rgba(...) using '0...255 and percent (integer) notation.
    • rgbFuncRe: Matches CSS1 'rgb(...) using '0...255 and percent (integer) notation.
    • rgbRe: Matches CSS4 'rgb(...) and rgba(...) functios using '0...255 and percent (float) notation.
  • CSS numbers
    • zeroTo100FloatPercentRe: Matches a 0 to 100% float as used in CSS color specifications.
    • zeroTo100PercentRe: Matches a 0 to 100% integer as used in CSS color specifications.
    • zeroTo1FloatRe: Matches a 0 to 1 float as used in CSS color specifications.
    • zeroTo255FloatRe: Matches a 0 to 255 float as used in CSS color specifications.
    • zeroTo255Re: Matches a 0 to 255 integer as used in CSS color specifications.
    • zeroTo360FloatRe: Matches a 0 to 360 float as used in CSS color specifications.
    • zeroTo360Re: Matches a 0 to 360 integer as used in CSS color specifications.
  • Date time
    • intlDateRe: Matches an international style 'YYYY/MM/DD' string.
    • iso8601DateRe: Matches an ISO 8601 date time like '20240101T1212Z.
    • iso8601DateReString: Matches the time designation portion of an ISO 8601 date+time.
    • iso8601DateTimeRe: Matches an ISO 8601 requiring both date and time components.
    • iso8601DayRe: An RE ready string that matches the day designation portion of an ISO 8601 date+time.
    • iso8601DayReString: An RE ready string that matches the day designation portion of an ISO 8601 date+time.
    • iso8601TimeRe: An RE ready string that matches the time designation portion of an ISO 8601 date+time.
    • militaryTimeRe: Matches military time style 'HHMM' string.
    • rfc2822DateRe: Matches an RFC 2822 style date like 'Mon, 6 Jan 1992 12:12 UTC'.
    • rfc2822DayRe: Matches the day designation portion of an RFC 2822 date+time.
    • rfc2822TimeRe: Matches the time designation portion of an RFC 2822 date+time.
    • timeRe: Matches a twelve hour time designation, requires AM or PM designation.
    • timezoneRe: Matches a general timezone designation; compliant with RFC 2822 timezone portion.
    • twentyFourHourTimeRe: Matches a twenty-four hour time designationAllows optional leading 0 in hour.
    • usDateRe: Matches a US style 'MM/DD/YYYY' string.
  • Domain names
    • domainLabelRe: Matches a non-tld domain label.
    • fqDomainNameRe: Matches fully qualified domain name (one or more subdomains + TLD).
    • localhostRe: Matches any representation of localhost; the special name, IPV4 loopbacks, or IPV6 loopbacks.
    • tldNameRe: Matches a Top Level Domain (TLD).
  • Identifiers
    • einRe: Matches a valid EIN number.
    • ssnRe: Matches a valid SSN.
    • uuidRe: Matches a UUID.
  • Javascript
    • jsReservedWordRe: Matches a JS resereved word.
    • jsVariableRe: Matches a valid JS variable name.
  • Network
    • ipAddressRe: Matches a string in IP address format.
    • ipHostRe: Matches a valid, non-localhost IP address.
    • ipV6Re: Matches a string in IPV6 format.
    • ipVFutureRe: Matches potential future IP protocols.
  • NPM
    • npmPackageNameRe: Matches an NPM package name.
    • npmPackageSpecRe: Matches an NPM package specification.
    • npmPackageTagRe: Matches an NPM package tag.
  • Numbers
    • floatRe: Matches a float in either plan or scientific format.
    • integerRe: Matches an integer.
    • plainFloatRe: Matches a plain (non-scientific notation) float.
    • scientificFloatRe: Matches a scientific notation float.
  • semver
    • semver2RangeRe: Matches a semantic versioning range specification.
    • semver2Re: Matches a semantic version string according to the Semantic Versioning 2.0.0 specification.
  • testCaptureGroups: Tests that a regular expression correctly extracts capture groups from input strings.
  • URL
    • commonUrlRe: Matches any of the "common" web URL types: 'mailto', 'http/https', 'ftp', and 'file'.
    • fileUrlRe: Matches a valid 'file' URL.
    • ftpUrlRe: Matches a valid 'ftp' URL.
    • httpUrlRe: Matches a valid 'http/https' URL.
    • mailtoUrlRe: Matches a valid 'mailto:' URL.
    • urlRe: Matches a valid, generic URL.

awsS3BucketNameRe ^{↱source code ⇧AWS index | global index}

Matches (most) valid S3 bucket name. Note awsS3BucketNameReString cannot be used for partial matches. Does not enforce 63 character limit. Due to checking for invalid S3 bucket names, awsS3BucketNameReString embeds '^' and '$' and so cannot be used for partial matches.

awsS3BucketNameReString ^{↱source code ⇧AWS index | global index}

An RE ready string that matches (most) valid S3 bucket names. When using this partial, you should verify the results do not match invalidS3PartialsReString. Because of the way the RE is constructed, this is one case where the partial string is not the same as that used to construct the awsS3BucketNameRe RE.

awsS3TaBucketNameRe ^{↱source code ⇧AWS index | global index}

Matches (most) S3 Transfer Acceleration compatible S3 bucket name. Note awsS3TaBucketNameReString cannot be used for partial matches.

awsS3TaBucketNameReString ^{↱source code ⇧AWS index | global index}

An RE ready string that matches (most) valid S3 Transfer Acceleration compatible bucket names. When using this partial, you should verify the results do not match invalidS3TaBucketNameReString. Because of the way the RE is constructed, this is one case where the partial string is not the same as that used to construct the awsS3TaBucketNameRe RE.

invalidS3TaBucketNameReString ^{↱source code ⇧AWS index | global index}

An RE ready string that matches excluded S3 Transfer Acceleration compatible bucket names that would be matched by awsS3TaBucketNameReString. Because of the way the RE is constructed, this is one case where the partial string is not the same as that used to construct the invalidS3TaBucketNameRe RE.

emailRe ^{↱source code ⇧Contacts index | global index}

Match most valid emails. Provides matching groups 1 (user name) and 2 (domain). When using the partial string to create a Re, you must use the 'u' flag.

usPhoneRe ^{↱source code ⇧Contacts index | global index}

Matches US phone numbers with optional country code and area code.

zipCodeRe ^{↱source code ⇧Contacts index | global index}

Matches 5 or 9 digit US zip codes.

cssColor3Re ^{↱source code ⇧CSS index | global index}

Matches CSS3 'hex, rgb, rgba, hsl, and predefined colors.

cssColorRe ^{↱source code ⇧CSS index | global index}

Matches CSS4 'hex, rgb, rgba, hsl, and predefined colors.

cssPreColors1Re ^{↱source code ⇧CSS index | global index}

Matches CSS1 predefined color names.

cssPreColors2Re ^{↱source code ⇧CSS index | global index}

Matches CSS2 predefined color names.

cssPreColors3Re ^{↱source code ⇧CSS index | global index}

Matches CSS3 predefined color names.

cssPreColorsRe ^{↱source code ⇧CSS index | global index}

Matches CSS4 predefined color names.

hexColorAlphaRe ^{↱source code ⇧CSS index | global index}

Matches hex specified RGBA colors with an alpha channel.

hexColorNoAlphaRe ^{↱source code ⇧CSS index | global index}

Matches hex specified RGB colors with no alpha channel.

hsl3Re ^{↱source code ⇧CSS index | global index}

Matches CSS3 'hsl(...) and hsla(...) deg and percent notation.

hslRe ^{↱source code ⇧CSS index | global index}

Matches CSS4 'hsl(...) and hsla(...) deg, grad, rad, turn and percent notation.

rgbaFuncRe ^{↱source code ⇧CSS index | global index}

Matches CSS3 'rgba(...) using '0...255 and percent (integer) notation.

rgbFuncRe ^{↱source code ⇧CSS index | global index}

Matches CSS1 'rgb(...) using '0...255 and percent (integer) notation.

rgbRe ^{↱source code ⇧CSS index | global index}

Matches CSS4 'rgb(...) and rgba(...) functios using '0...255 and percent (float) notation.

zeroTo100FloatPercentRe ^{↱source code ⇧CSS numbers index | global index}

Matches a 0 to 100% float as used in CSS color specifications.

zeroTo100PercentRe ^{↱source code ⇧CSS numbers index | global index}

Matches a 0 to 100% integer as used in CSS color specifications.

zeroTo1FloatRe ^{↱source code ⇧CSS numbers index | global index}

Matches a 0 to 1 float as used in CSS color specifications.

zeroTo255FloatRe ^{↱source code ⇧CSS numbers index | global index}

Matches a 0 to 255 float as used in CSS color specifications.

zeroTo255Re ^{↱source code ⇧CSS numbers index | global index}

Matches a 0 to 255 integer as used in CSS color specifications.

zeroTo360FloatRe ^{↱source code ⇧CSS numbers index | global index}

Matches a 0 to 360 float as used in CSS color specifications.

zeroTo360Re ^{↱source code ⇧CSS numbers index | global index}

Matches a 0 to 360 integer as used in CSS color specifications.

intlDateRe ^{↱source code ⇧Date time index | global index}

Matches an international style 'YYYY/MM/DD' string. Accepts separators '.', '/', '-'. Will except 1 or 2 digits for month and day and 1-4 digits for the year. Also accepts a + or - before the year. Provides capture groups:

• Group 1: BCE/CE indicator
• Group 2: year
• Group 3: month
• Group 4: day

iso8601DateRe ^{↱source code ⇧Date time index | global index}

Matches an ISO 8601 date time like '20240101T1212Z. Provides matching groups:

• Group 1: year
• Group 3: month
• Group 4: day of month
• Group 5: week of year
• Group 6: day of week date
• Group 7: ordinal or Julian date
• Group 8: special end of day time
• Group 10: hour
• Group 11: decimal fraction of hour
• Group 13: minute
• Group 14: decimal fraction of minute
• Group 15: seconds
• Group 16: decimal fraction of a second
• Group 17: timezone designation

(Groups 2, 11, and 13 are internal back references.)

iso8601DateReString ^{↱source code ⇧Date time index | global index}

Matches the time designation portion of an ISO 8601 date+time. Provides matching groups:

• Group 1: year
• Group 3: month
• Group 4: day of month
• Group 5: week of year
• Group 6: day of week date
• Group 7: ordinal or Julian date
• Group 8: special end of day time
• Group 10: hour
• Group 11: decimal fraction of hour
• Group 13: minute
• Group 14: decimal fraction of minute
• Group 15: seconds
• Group 16: decimal fraction of a second
• Group 17: timezone designation

iso8601DateTimeRe ^{↱source code ⇧Date time index | global index}

Matches an ISO 8601 requiring both date and time components. See iso8601DateRe for matching groups.

iso8601DayRe ^{↱source code ⇧Date time index | global index}

An RE ready string that matches the day designation portion of an ISO 8601 date+time. Provides matching groups:

• Group 1: year
• Group 3: month
• Group 4: day of month
• Group 5: week of year
• Group 6: day of week date
• Group 7: ordinal or Julian date

iso8601DayReString ^{↱source code ⇧Date time index | global index}

An RE ready string that matches the day designation portion of an ISO 8601 date+time. Provides matching groups:

• Group 1: year
• Group 3: month
• Group 4: day of month
• Group 5: week of year
• Group 6: day of week date
• Group 7: ordinal or Julian date

iso8601TimeRe ^{↱source code ⇧Date time index | global index}

An RE ready string that matches the time designation portion of an ISO 8601 date+time. Provides matching groups:

• Group 1: special end of day time
• Group 3: hours
• Group 4: fraction of hour
• Group 6: minutes
• Group 7: fraction of minute
• Group 8: seconds
• Group 9: fraction of seconds
• Group 10: timezone

(Groups 2 and 5 are internal backreferences for separator consistency)

militaryTimeRe ^{↱source code ⇧Date time index | global index}

Matches military time style 'HHMM' string. Provides capture groups:

• Group 1: special 2400 time
• Group 2: hour
• Group 3: minutes

rfc2822DateRe ^{↱source code ⇧Date time index | global index}

Matches an RFC 2822 style date like 'Mon, 6 Jan 1992 12:12 UTC'. Provides matching groups:

• Group 1: day of week
• Group 2: day of month
• Group 3: month name
• Group 4: year
• Group 5: hour
• Group 6: min
• Group 7: second
• Group 8: time zone

rfc2822DayRe ^{↱source code ⇧Date time index | global index}

Matches the day designation portion of an RFC 2822 date+time. Provides matching groups:

• Group 1: day of week name
• Group 2: day of month
• Group 3: month name
• Group 4: year

rfc2822TimeRe ^{↱source code ⇧Date time index | global index}

Matches the time designation portion of an RFC 2822 date+time. Provides matching groups:

• Group 1: hour
• Group 2: minutes
• Group 3: seconds
• Group 4: timezone

timeRe ^{↱source code ⇧Date time index | global index}

Matches a twelve hour time designation, requires AM or PM designation. Allows optional leading 0 in hour. Provides matching groups:

• Group 1: hour
• Group 2: minutes
• Group 3: seconds, without decimal fractions
• Group 4: decimal fraction seconds
• Group 5: AM/PM indicator

timezoneRe ^{↱source code ⇧Date time index | global index}

Matches a general timezone designation; compliant with RFC 2822 timezone portion. Provides matching groups:

• Group 1: timezone

twentyFourHourTimeRe ^{↱source code ⇧Date time index | global index}

Matches a twenty-four hour time designationAllows optional leading 0 in hour. Provides matching groups:

• Group 1: special 24:00 designation with optional seconds
• Group 2: hour
• Group 3: minutes
• Group 4: seconds, without decimal fractions
• Group 5: decimal fraction seconds

usDateRe ^{↱source code ⇧Date time index | global index}

Matches a US style 'MM/DD/YYYY' string. Accepts separators '.', '/', '-'. Will except 1 or 2 digits for month and day and 1-4 digits for the year. Also accepts a + or - before the year. Provides capture groups:

• Group 1: month
• Group 2: day of month
• Group 3: BCE/CE indicator
• Group 4: year

domainLabelRe ^{↱source code ⇧Domain names index | global index}

Matches a non-tld domain label. Enforces the 63 byte domain label limit for non-international (all ASCII) labels. See domain name rules. When using the partial string to create a Re, you must use the 'u' or 'v' flag.

fqDomainNameRe ^{↱source code ⇧Domain names index | global index}

Matches fully qualified domain name (one or more subdomains + TLD). Partially enforces the 255 byte FQ domain name limit, but this is only valid for non-international (all ASCII) domain names because we can only count characters. When using the partial string to create a Re, you must use the 'u' or 'v' flag.

localhostRe ^{↱source code ⇧Domain names index | global index}

Matches any representation of localhost; the special name, IPV4 loopbacks, or IPV6 loopbacks.

tldNameRe ^{↱source code ⇧Domain names index | global index}

Matches a Top Level Domain (TLD). See domain name rules. When using the partial string to create a Re, you must use the 'u' or 'v' flag.

einRe ^{↱source code ⇧Identifiers index | global index}

Matches a valid EIN number.

ssnRe ^{↱source code ⇧Identifiers index | global index}

Matches a valid SSN. Provides 3 matching groups, 1 (area number), 2 (group number), and 3 (serial number).

uuidRe ^{↱source code ⇧Identifiers index | global index}

Matches a UUID.

jsReservedWordRe ^{↱source code ⇧Javascript index | global index}

Matches a JS resereved word.

jsVariableRe ^{↱source code ⇧Javascript index | global index}

Matches a valid JS variable name.

ipAddressRe ^{↱source code ⇧Network index | global index}

Matches a string in IP address format. Use 'ipHostRe' to match actually valid IP addresses.

ipHostRe ^{↱source code ⇧Network index | global index}

Matches a valid, non-localhost IP address.

ipV6Re ^{↱source code ⇧Network index | global index}

Matches a string in IPV6 format.

ipVFutureRe ^{↱source code ⇧Network index | global index}

Matches potential future IP protocols.

npmPackageNameRe ^{↱source code ⇧NPM index | global index}

Matches an NPM package name. Provides matching groups 1 (org name, if any) and 2 (package basename).

npmPackageSpecRe ^{↱source code ⇧NPM index | global index}

Matches an NPM package specification. Note, because any string that cannot be confused with a semver is, in theory, a valid tag, this could be any string.

npmPackageTagRe ^{↱source code ⇧NPM index | global index}

Matches an NPM package tag. A tag can, in theory, be anything that cannot be confused with a semver range. Due to the requirements of RE construction, the RE string ends up being useless for partial matches so is NOT exported.

floatRe ^{↱source code ⇧Numbers index | global index}

Matches a float in either plan or scientific format.

integerRe ^{↱source code ⇧Numbers index | global index}

Matches an integer.

plainFloatRe ^{↱source code ⇧Numbers index | global index}

Matches a plain (non-scientific notation) float.

scientificFloatRe ^{↱source code ⇧Numbers index | global index}

Matches a scientific notation float.

semver2RangeRe ^{↱source code ⇧semver index | global index}

Matches a semantic versioning range specification. Allows for optional 'v' prefix (equivalent to '='), and otherwise follows the original spec's BNF grammar. This means that an 'and' space between versions must be a single space and also requires exactly one space around hyphenated ranges.

semver2Re ^{↱source code ⇧semver index | global index}

Matches a semantic version string according to the Semantic Versioning 2.0.0 specification. Provides matching groups:

• Group 1: major version
• Group 2: minor version
• Group 3: patch version
• Group 4: pre-release version (if present)
• Group 5: build metadata (if present)

testCaptureGroups ^{↱source code ⇧global index}

Tests that a regular expression correctly extracts capture groups from input strings.

This function supports two modes:

1. Sequential mode: Tests capture groups 1, 2, 3, ... in order (when groupNumbers is omitted)
2. Numbered mode: Tests specific capture group numbers (when groupNumbers is provided)

The numbered mode is useful for regexes with internal non-capturing groups, backreferences, or alternations that create sparse or non-sequential capture group numbering.

Param	Type	Description
re	RegExp	The regular expression to test
inputs	Array.<string>	Array of input strings to test against the regex
expectedMatches	`Array.<Array.<(string	undefined)>>`
[groupNumbers]	Array.<number>	Optional array of capture group numbers to test. If omitted, tests groups 1, 2, 3, ... sequentially.
desc	string	Description of the test (shown in test output)

Examples:

// Sequential mode (tests groups 1, 2, 3)
testCaptureGroups(
  /(\d{4})-(\d{2})-(\d{2})/,
  ['2024-01-15'],
  [['2024', '01', '15']],
  'date capture groups'
)

// Numbered mode (tests specific group numbers: 1, 3, 5)
testCaptureGroups(
  /^(https?):\/\/((?:\w+\.)*\w+)(:\d+)?(\/.*)?$/,
  ['https://example.com:8080/path'],
  [['https', 'example.com', ':8080', '/path']],
  [1, 2, 3, 4], // explicitly specify which groups to test
  'URL capture groups'
)

commonUrlRe ^{↱source code ⇧URL index | global index}

Matches any of the "common" web URL types: 'mailto', 'http/https', 'ftp', and 'file'. You must use the either the 'u' or 'v' flag when using the Re string.

fileUrlRe ^{↱source code ⇧URL index | global index}

Matches a valid 'file' URL. Provides capture groups:

• Group 1: host
• Group 2: path

You must use the either the 'u' or 'v' flag when using the Re string.

ftpUrlRe ^{↱source code ⇧URL index | global index}

Matches a valid 'ftp' URL. Provides capture groups:

• Group 1: username
• Group 2: user password
• Group 3: host or IP
• Group 4: port
• Group 5: path

You must use the either the 'u' or 'v' flag when using the Re string.

httpUrlRe ^{↱source code ⇧URL index | global index}

Matches a valid 'http/https' URL. Provides capture groups:

• Group 1: protocol
• Group 2: username
• Group 3: user password
• Group 4: host or IP
• Group 5: port
• Group 6: path
• Group 7: query string
• Group 8: fragment

You must use the either the 'u' or 'v' flag when using the Re string.

mailtoUrlRe ^{↱source code ⇧URL index | global index}

Matches a valid 'mailto:' URL. Provides a single capture group:

• Group 1: email address

You must use the either the 'u' or 'v' flag when using the Re string.

urlRe ^{↱source code ⇧URL index | global index}

Matches a valid, generic URL. Provides capture groups:

• Group 1: schema
• Group 2: server/authority
• Group 3: path
• Group 4: query part
• Group 5: intra-page link/fragment

Note, a URL always has scheme, and at a minimum a server/authority or path, and may have both. The query and fragment components are always optional. For general usage, you might want to use the more specific Res for specific protocols or the commonUrlRe.

Domain name rules

Unfortunately, there isn't clear consensus on what is allowed in a subdomain vs a top level domain (TLD); referred to collectively as 'domain labels'. So, here are the rules we follow:

• Domain labels may no more than 63 bytes in length.
• Labels are composed of alpha-numeric characters (a-z, 0-9, and any non-ASCII Unicode character) and hyphens ('-'), except:
  • the label may not begin or end with a hyphen,
  • may not consist of a single digit,
  • the label must not have consecutive hyphens in the 3rd and 4th position. E.g. 'xy--z' is invalid.¹
• TLDs must be at least two bytes (two ASCII characters or a single Unicode character) and may not be composed only of digits.
• A fully qualified domain is limited to 255 bytes in total.

Footnotes

1. The DNS protocol only allows a-z, 0-9, and '-' in domain labels. International domains are encoded as special 'xn--' domains. E.g., 'कॉम"' is encoded as 'xn--11b4c3d'. This is why hyphens in the third and fourth position are restricted. So, while 'xn--11b4c3d' is a valid domain, you can't register such domains directly. You would register the international domain and it's translated to an 'xn--' domain in the background. ↩