micromark-util-character

micromark utility to handle character codes.

Contents

• What is this?
• When should I use this?
• Install
• Use
• API
  • asciiAlpha(code)
  • asciiAlphanumeric(code)
  • asciiAtext(code)
  • asciiControl(code)
  • asciiDigit(code)
  • asciiHexDigit(code)
  • asciiPunctuation(code)
  • markdownLineEnding(code)
  • markdownLineEndingOrSpace(code)
  • markdownSpace(code)
  • unicodePunctuation(code)
  • unicodeWhitespace(code)
• Types
• Compatibility
• Security
• Contribute
• License

What is this?

This package exposes algorithms to check whether characters match groups.

When should I use this?

This package might be useful when you are making your own micromark extensions.

Install

This package is ESM only. In Node.js (version 16+), install with npm:

npm install micromark-util-character

In Deno with esm.sh:

import * as character from 'https://esm.sh/micromark-util-character@1'

In browsers with esm.sh:

<script type="module">
  import * as character from 'https://esm.sh/micromark-util-character@1?bundle'
</script>

Use

import {asciiAlpha} from 'micromark-util-character'

console.log(asciiAlpha(64)) // false
console.log(asciiAlpha(65)) // true

API

This module exports the identifiers asciiAlpha, asciiAlphanumeric, asciiAtext, asciiControl, asciiDigit, asciiHexDigit, asciiPunctuation, markdownLineEnding, markdownLineEndingOrSpace, markdownSpace, unicodePunctuation, unicodeWhitespace. There is no default export.

asciiAlpha(code)

Check whether the character code represents an ASCII alpha (a through z, case insensitive).

An ASCII alpha is an ASCII upper alpha or ASCII lower alpha.

An ASCII upper alpha is a character in the inclusive range U+0041 (A) to U+005A (Z).

An ASCII lower alpha is a character in the inclusive range U+0061 (a) to U+007A (z).

Parameters

• code (Code) — code

Returns

Whether it matches (boolean).

asciiAlphanumeric(code)

Check whether the character code represents an ASCII alphanumeric (a through z, case insensitive, or 0 through 9).

An ASCII alphanumeric is an ASCII digit (see asciiDigit) or ASCII alpha (see asciiAlpha).

Parameters

• code (Code) — code

Returns

Whether it matches (boolean).

asciiAtext(code)

Check whether the character code represents an ASCII atext.

atext is an ASCII alphanumeric (see asciiAlphanumeric), or a character in the inclusive ranges U+0023 NUMBER SIGN (#) to U+0027 APOSTROPHE ('), U+002A ASTERISK (*), U+002B PLUS SIGN (+), U+002D DASH (-), U+002F SLASH (/), U+003D EQUALS TO (=), U+003F QUESTION MARK (?), U+005E CARET (^) to U+0060 GRAVE ACCENT (`), or U+007B LEFT CURLY BRACE ({) to U+007E TILDE (~) ([RFC5322]).

See [RFC5322]:
Internet Message Format.
P. Resnick.
IETF.

Parameters

• code (Code) — code

Returns

Whether it matches (boolean).

asciiControl(code)

Check whether a character code is an ASCII control character.

An ASCII control is a character in the inclusive range U+0000 NULL (NUL) to U+001F (US), or U+007F (DEL).

Parameters

• code (Code) — code

Returns

Whether it matches (boolean).

asciiDigit(code)

Check whether the character code represents an ASCII digit (0 through 9).

An ASCII digit is a character in the inclusive range U+0030 (0) to U+0039 (9).

Parameters

• code (Code) — code

Returns

Whether it matches (boolean).

asciiHexDigit(code)

Check whether the character code represents an ASCII hex digit (a through f, case insensitive, or 0 through 9).

An ASCII hex digit is an ASCII digit (see asciiDigit), ASCII upper hex digit, or an ASCII lower hex digit.

An ASCII upper hex digit is a character in the inclusive range U+0041 (A) to U+0046 (F).

An ASCII lower hex digit is a character in the inclusive range U+0061 (a) to U+0066 (f).

Parameters

• code (Code) — code

Returns

Whether it matches (boolean).

asciiPunctuation(code)

Check whether the character code represents ASCII punctuation.

An ASCII punctuation is a character in the inclusive ranges U+0021 EXCLAMATION MARK (!) to U+002F SLASH (/), U+003A COLON (:) to U+0040 AT SIGN (@), U+005B LEFT SQUARE BRACKET ([) to U+0060 GRAVE ACCENT (`), or U+007B LEFT CURLY BRACE ({) to U+007E TILDE (~).

Parameters

• code (Code) — code

Returns

Whether it matches (boolean).

markdownLineEnding(code)

Check whether a character code is a markdown line ending.

A markdown line ending is the virtual characters M-0003 CARRIAGE RETURN LINE FEED (CRLF), M-0004 LINE FEED (LF) and M-0005 CARRIAGE RETURN (CR).

In micromark, the actual character U+000A LINE FEED (LF) and U+000D CARRIAGE RETURN (CR) are replaced by these virtual characters depending on whether they occurred together.

Parameters

• code (Code) — code

Returns

Whether it matches (boolean).

markdownLineEndingOrSpace(code)

Check whether a character code is a markdown line ending (see markdownLineEnding) or markdown space (see markdownSpace).

Parameters

• code (Code) — code

Returns

Whether it matches (boolean).

markdownSpace(code)

Check whether a character code is a markdown space.

A markdown space is the concrete character U+0020 SPACE (SP) and the virtual characters M-0001 VIRTUAL SPACE (VS) and M-0002 HORIZONTAL TAB (HT).

In micromark, the actual character U+0009 CHARACTER TABULATION (HT) is replaced by one M-0002 HORIZONTAL TAB (HT) and between 0 and 3 M-0001 VIRTUAL SPACE (VS) characters, depending on the column at which the tab occurred.

Parameters

• code (Code) — code

Returns

Whether it matches (boolean).

unicodePunctuation(code)

Check whether the character code represents Unicode punctuation.

A Unicode punctuation is a character in the Unicode Pc (Punctuation, Connector), Pd (Punctuation, Dash), Pe (Punctuation, Close), Pf (Punctuation, Final quote), Pi (Punctuation, Initial quote), Po (Punctuation, Other), or Ps (Punctuation, Open) categories, or an ASCII punctuation (see asciiPunctuation) ([UNICODE]).

See [UNICODE]:
The Unicode Standard.
Unicode Consortium.

Parameters

• code (Code) — code

Returns

Whether it matches (boolean).

unicodeWhitespace(code)

Check whether the character code represents Unicode whitespace.

Note that this does handle micromark specific markdown whitespace characters. See markdownLineEndingOrSpace to check that.

A Unicode whitespace is a character in the Unicode Zs (Separator, Space) category, or U+0009 CHARACTER TABULATION (HT), U+000A LINE FEED (LF), U+000C (FF), or U+000D CARRIAGE RETURN (CR) ([UNICODE]).

See [UNICODE]:
The Unicode Standard.
Unicode Consortium.

Parameters

• code (Code) — code

Returns

Whether it matches (boolean).

Types

This package is fully typed with TypeScript. It exports no additional types.

Compatibility

Projects maintained by the unified collective are compatible with maintained versions of Node.js.

When we cut a new major release, we drop support for unmaintained versions of Node. This means we try to keep the current release line, micromark-util-character@^2, compatible with Node.js 16. This package works with micromark@^3.

Security

This package is safe. See security.md in micromark/.github for how to submit a security report.

Contribute

See contributing.md in micromark/.github for ways to get started. See support.md for ways to get help.

This project has a code of conduct. By interacting with this repository, organisation, or community you agree to abide by its terms.

License

MIT © Titus Wormer