hexo-generator/node_modules/markdown-it-cjk-breaks/index.js

'use strict';

var eastAsianWidth = require('eastasianwidth').eastAsianWidth;


function is_surrogate(c1, c2) {
  return c1 >= 0xD800 && c1 <= 0xDBFF && c2 >= 0xDC00 && c2 <= 0xDFFF;
}


function is_hangul(c) {
  // require('unicode-10.0.0/Script/Hangul/regex')
  /* eslint-disable max-len */
  return /[\u1100-\u11FF\u302E\u302F\u3131-\u318E\u3200-\u321E\u3260-\u327E\uA960-\uA97C\uAC00-\uD7A3\uD7B0-\uD7C6\uD7CB-\uD7FB\uFFA0-\uFFBE\uFFC2-\uFFC7\uFFCA-\uFFCF\uFFD2-\uFFD7\uFFDA-\uFFDC]/.test(c);
  /* eslint-enable max-len */
}


function process_inlines(tokens) {
  var i, j, last, next, c1, c2, remove_break;

  for (i = 0; i < tokens.length; i++) {
    if (tokens[i].type !== 'softbreak') continue;

    // default last/next character to space
    last = next = ' ';

    for (j = i - 1; j >= 0; j--) {
      if (tokens[j].type !== 'text') continue;

      c1 = tokens[j].content.charCodeAt(tokens[j].content.length - 2);
      c2 = tokens[j].content.charCodeAt(tokens[j].content.length - 1);

      last = tokens[j].content.slice(is_surrogate(c1, c2) ? -2 : -1);
      break;
    }

    for (j = i + 1; j < tokens.length; j++) {
      if (tokens[j].type !== 'text') continue;

      c1 = tokens[j].content.charCodeAt(0);
      c2 = tokens[j].content.charCodeAt(1);

      next = tokens[j].content.slice(0, is_surrogate(c1, c2) ? 2 : 1);
      break;
    }

    remove_break = false;

    // remove newline if it's adjacent to ZWSP
    if (last === '\u200b' || next === '\u200b') remove_break = true;

    // remove newline if both characters are fullwidth (F), wide (W) or
    // halfwidth (H), but not Hangul
    if (/^[FWH]$/.test(eastAsianWidth(last)) && /^[FWH]$/.test(eastAsianWidth(next))) {
      if (!is_hangul(last) && !is_hangul(next)) remove_break = true;
    }

    if (remove_break) {
      tokens[i].type    = 'text';
      tokens[i].content = '';
    }
  }
}


function cjk_breaks(state) {
  for (var blkIdx = state.tokens.length - 1; blkIdx >= 0; blkIdx--) {
    if (state.tokens[blkIdx].type !== 'inline') continue;

    process_inlines(state.tokens[blkIdx].children, state);
  }
}


module.exports = function cjk_breaks_plugin(md) {
  md.core.ruler.push('cjk_breaks', cjk_breaks);
};