markdown-it/lib/rules_inline/escape.js

// Process escaped chars and hardbreaks

'use strict';

var isSpace = require('../common/utils').isSpace;

var ESCAPED = [];

for (var i = 0; i < 256; i++) { ESCAPED.push(0); }

'\\!"#$%&\'()*+,./:;<=>?@[]^_`{|}~-'
  .split('').forEach(function (ch) { ESCAPED[ch.charCodeAt(0)] = 1; });


module.exports = function escape(state, silent) {
  var ch1, ch2, origStr, escapedStr, token, pos = state.pos, max = state.posMax;

  if (state.src.charCodeAt(pos) !== 0x5C/* \ */) return false;
  pos++;

  // '\' at the end of the inline block
  if (pos >= max) return false;

  ch1 = state.src.charCodeAt(pos);

  if (ch1 === 0x0A) {
    if (!silent) {
      state.push('hardbreak', 'br', 0);
    }

    pos++;
    // skip leading whitespaces from next line
    while (pos < max) {
      ch1 = state.src.charCodeAt(pos);
      if (!isSpace(ch1)) break;
      pos++;
    }

    state.pos = pos;
    return true;
  }

  escapedStr = state.src[pos];

  if (ch1 >= 0xD800 && ch1 <= 0xDBFF && pos + 1 < max) {
    ch2 = state.src.charCodeAt(pos + 1);

    if (ch2 >= 0xDC00 && ch2 <= 0xDFFF) {
      escapedStr += state.src[pos + 1];
      pos++;
    }
  }

  origStr = '\\' + escapedStr;

  if (!silent) {
    token = state.push('text_special', '', 0);

    if (ch1 < 256 && ESCAPED[ch1] !== 0) {
      token.content = escapedStr;
    } else {
      token.content = origStr;
    }

    token.markup = origStr;
    token.info   = 'escape';
  }

  state.pos = pos + 1;
  return true;
};