posthtml-parser/index.js

const {Parser} = require('htmlparser2');

/**
 * @see https://github.com/fb55/htmlparser2/wiki/Parser-options
 */
const defaultOptions = {lowerCaseTags: false, lowerCaseAttributeNames: false};

const defaultDirectives = [{name: '!doctype', start: '<', end: '>'}];

/**
 * Parse html to PostHTMLTree
 * @param  {String} html
 * @param  {Object} [options=defaultOptions]
 * @return {PostHTMLTree}
 */
function postHTMLParser(html, options) {
  const bufArray = [];
  const results = [];

  bufArray.last = function () {
    return this[this.length - 1];
  };

  function isDirective({name}, tag) {
    if (name instanceof RegExp) {
      const regex = new RegExp(name.source, 'i');

      return regex.test(tag);
    }

    if (tag !== name) {
      return false;
    }

    return true;
  }

  function parserDirective(name, data) {
    const directives = [].concat(defaultDirectives, options.directives || []);
    const last = bufArray.last();

    for (const directive of directives) {
      const directiveText = directive.start + data + directive.end;

      name = name.toLowerCase();
      if (isDirective(directive, name)) {
        if (!last) {
          results.push(directiveText);
          return;
        }

        if (last.content === undefined) {
          last.content = [];
        }

        last.content.push(directiveText);
      }
    }
  }

  function normalizeArributes(attrs) {
    const result = {};
    Object.keys(attrs).forEach(key => {
      const object = {};
      object[key] = attrs[key].replace(/&quot;/g, '"');
      Object.assign(result, object);
    });

    return result;
  }

  const parser = new Parser({
    onprocessinginstruction: parserDirective,
    oncomment(data) {
      const comment = `<!--${data}-->`;
      const last = bufArray.last();

      if (!last) {
        results.push(comment);
        return;
      }

      if (last.content === undefined) {
        last.content = [];
      }

      last.content.push(comment);
    },
    onopentag(tag, attrs) {
      const buf = {tag};

      if (Object.keys(attrs).length > 0) {
        buf.attrs = normalizeArributes(attrs);
      }

      bufArray.push(buf);
    },
    onclosetag() {
      const buf = bufArray.pop();

      if (!bufArray.length > 0) {
        results.push(buf);
        return;
      }

      const last = bufArray.last();
      if (!Array.isArray(last.content)) {
        last.content = [];
      }

      last.content.push(buf);
    },
    ontext(text) {
      const last = bufArray.last();

      if (!last) {
        results.push(text);
        return;
      }

      if (last.content && last.content.length > 0 && typeof last.content[last.content.length - 1] === 'string') {
        last.content[last.content.length - 1] = `${last.content[last.content.length - 1]}${text}`;
        return;
      }

      if (last.content === undefined) {
        last.content = [];
      }

      last.content.push(text);
    }
  }, options || defaultOptions);

  parser.write(html);
  parser.end();

  return results;
}

function parserWrapper(...args) {
  let option;

  function parser(html) {
    const opt = {...defaultOptions, ...option};
    return postHTMLParser(html, opt);
  }

  if (
    args.length === 1 &&
    Boolean(args[0]) &&
    args[0].constructor.name === 'Object'
  ) {
    option = args[0];
    return parser;
  }

  option = args[1];
  return parser(args[0]);
}

module.exports = parserWrapper;
module.exports.defaultOptions = defaultOptions;
module.exports.defaultDirectives = defaultDirectives;