MZC/KnowMathBot/frontend/node_modules/micromark-core-commonmark/lib/heading-atx.js

/**
 * @import {
 *   Construct,
 *   Resolver,
 *   State,
 *   TokenizeContext,
 *   Tokenizer,
 *   Token
 * } from 'micromark-util-types'
 */

import { factorySpace } from 'micromark-factory-space';
import { markdownLineEndingOrSpace, markdownLineEnding, markdownSpace } from 'micromark-util-character';
import { splice } from 'micromark-util-chunked';
/** @type {Construct} */
export const headingAtx = {
  name: 'headingAtx',
  resolve: resolveHeadingAtx,
  tokenize: tokenizeHeadingAtx
};

/** @type {Resolver} */
function resolveHeadingAtx(events, context) {
  let contentEnd = events.length - 2;
  let contentStart = 3;
  /** @type {Token} */
  let content;
  /** @type {Token} */
  let text;

  // Prefix whitespace, part of the opening.
  if (events[contentStart][1].type === "whitespace") {
    contentStart += 2;
  }

  // Suffix whitespace, part of the closing.
  if (contentEnd - 2 > contentStart && events[contentEnd][1].type === "whitespace") {
    contentEnd -= 2;
  }
  if (events[contentEnd][1].type === "atxHeadingSequence" && (contentStart === contentEnd - 1 || contentEnd - 4 > contentStart && events[contentEnd - 2][1].type === "whitespace")) {
    contentEnd -= contentStart + 1 === contentEnd ? 2 : 4;
  }
  if (contentEnd > contentStart) {
    content = {
      type: "atxHeadingText",
      start: events[contentStart][1].start,
      end: events[contentEnd][1].end
    };
    text = {
      type: "chunkText",
      start: events[contentStart][1].start,
      end: events[contentEnd][1].end,
      contentType: "text"
    };
    splice(events, contentStart, contentEnd - contentStart + 1, [['enter', content, context], ['enter', text, context], ['exit', text, context], ['exit', content, context]]);
  }
  return events;
}

/**
 * @this {TokenizeContext}
 *   Context.
 * @type {Tokenizer}
 */
function tokenizeHeadingAtx(effects, ok, nok) {
  let size = 0;
  return start;

  /**
   * Start of a heading (atx).
   *
   * ```markdown
   * > | ## aa
   *     ^
   * ```
   *
   * @type {State}
   */
  function start(code) {
    // To do: parse indent like `markdown-rs`.
    effects.enter("atxHeading");
    return before(code);
  }

  /**
   * After optional whitespace, at `#`.
   *
   * ```markdown
   * > | ## aa
   *     ^
   * ```
   *
   * @type {State}
   */
  function before(code) {
    effects.enter("atxHeadingSequence");
    return sequenceOpen(code);
  }

  /**
   * In opening sequence.
   *
   * ```markdown
   * > | ## aa
   *     ^
   * ```
   *
   * @type {State}
   */
  function sequenceOpen(code) {
    if (code === 35 && size++ < 6) {
      effects.consume(code);
      return sequenceOpen;
    }

    // Always at least one `#`.
    if (code === null || markdownLineEndingOrSpace(code)) {
      effects.exit("atxHeadingSequence");
      return atBreak(code);
    }
    return nok(code);
  }

  /**
   * After something, before something else.
   *
   * ```markdown
   * > | ## aa
   *       ^
   * ```
   *
   * @type {State}
   */
  function atBreak(code) {
    if (code === 35) {
      effects.enter("atxHeadingSequence");
      return sequenceFurther(code);
    }
    if (code === null || markdownLineEnding(code)) {
      effects.exit("atxHeading");
      // To do: interrupt like `markdown-rs`.
      // // Feel free to interrupt.
      // tokenizer.interrupt = false
      return ok(code);
    }
    if (markdownSpace(code)) {
      return factorySpace(effects, atBreak, "whitespace")(code);
    }

    // To do: generate `data` tokens, add the `text` token later.
    // Needs edit map, see: `markdown.rs`.
    effects.enter("atxHeadingText");
    return data(code);
  }

  /**
   * In further sequence (after whitespace).
   *
   * Could be normal “visible” hashes in the heading or a final sequence.
   *
   * ```markdown
   * > | ## aa ##
   *           ^
   * ```
   *
   * @type {State}
   */
  function sequenceFurther(code) {
    if (code === 35) {
      effects.consume(code);
      return sequenceFurther;
    }
    effects.exit("atxHeadingSequence");
    return atBreak(code);
  }

  /**
   * In text.
   *
   * ```markdown
   * > | ## aa
   *        ^
   * ```
   *
   * @type {State}
   */
  function data(code) {
    if (code === null || code === 35 || markdownLineEndingOrSpace(code)) {
      effects.exit("atxHeadingText");
      return atBreak(code);
    }
    effects.consume(code);
    return data;
  }
}