ui/node_modules/micromark-util-character/index.js

/**
 * @typedef {import('micromark-util-types').Code} Code
 */

import {unicodePunctuationRegex} from './lib/unicode-punctuation-regex.js'

/**
 * 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`).
 *
 * @param code
 *   Code.
 * @returns
 *   Whether it matches.
 */
export const asciiAlpha = regexCheck(/[A-Za-z]/)

/**
 * 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`).
 *
 * @param code
 *   Code.
 * @returns
 *   Whether it matches.
 */
export const asciiAlphanumeric = regexCheck(/[\dA-Za-z]/)

/**
 * 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 (`~`).
 *
 * See:
 * **\[RFC5322]**:
 * [Internet Message Format](https://tools.ietf.org/html/rfc5322).
 * P. Resnick.
 * IETF.
 *
 * @param code
 *   Code.
 * @returns
 *   Whether it matches.
 */
export const asciiAtext = regexCheck(/[#-'*+\--9=?A-Z^-~]/)

/**
 * 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).
 *
 * @param {Code} code
 *   Code.
 * @returns {boolean}
 *   Whether it matches.
 */
export function asciiControl(code) {
  return (
    // Special whitespace codes (which have negative values), C0 and Control
    // character DEL
    code !== null && (code < 32 || code === 127)
  )
}

/**
 * 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`).
 *
 * @param code
 *   Code.
 * @returns
 *   Whether it matches.
 */
export const asciiDigit = regexCheck(/\d/)

/**
 * 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`).
 *
 * @param code
 *   Code.
 * @returns
 *   Whether it matches.
 */
export const asciiHexDigit = regexCheck(/[\dA-Fa-f]/)

/**
 * 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 (`~`).
 *
 * @param code
 *   Code.
 * @returns
 *   Whether it matches.
 */
export const asciiPunctuation = regexCheck(/[!-/:-@[-`{-~]/)

/**
 * 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.
 *
 * @param {Code} code
 *   Code.
 * @returns {boolean}
 *   Whether it matches.
 */
export function markdownLineEnding(code) {
  return code !== null && code < -2
}

/**
 * Check whether a character code is a markdown line ending (see
 * `markdownLineEnding`) or markdown space (see `markdownSpace`).
 *
 * @param {Code} code
 *   Code.
 * @returns {boolean}
 *   Whether it matches.
 */
export function markdownLineEndingOrSpace(code) {
  return code !== null && (code < 0 || code === 32)
}

/**
 * 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.
 *
 * @param {Code} code
 *   Code.
 * @returns {boolean}
 *   Whether it matches.
 */
export function markdownSpace(code) {
  return code === -2 || code === -1 || code === 32
}

// Size note: removing ASCII from the regex and using `asciiPunctuation` here
// In fact adds to the bundle size.
/**
 * 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`).
 *
 * See:
 * **\[UNICODE]**:
 * [The Unicode Standard](https://www.unicode.org/versions/).
 * Unicode Consortium.
 *
 * @param code
 *   Code.
 * @returns
 *   Whether it matches.
 */
export const unicodePunctuation = regexCheck(unicodePunctuationRegex)

/**
 * 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](https://www.unicode.org/versions/).
 * Unicode Consortium.
 *
 * @param code
 *   Code.
 * @returns
 *   Whether it matches.
 */
export const unicodeWhitespace = regexCheck(/\s/)

/**
 * Create a code check from a regex.
 *
 * @param {RegExp} regex
 * @returns {(code: Code) => boolean}
 */
function regexCheck(regex) {
  return check

  /**
   * Check whether a code matches the bound regex.
   *
   * @param {Code} code
   *   Character code.
   * @returns {boolean}
   *   Whether the character code matches the bound regex.
   */
  function check(code) {
    return code !== null && regex.test(String.fromCharCode(code))
  }
}