githubmirror/markdown-here

src/common/jsHtmlToText.js
270 строк7 KB
Adam Pritchard
Fixed issue #7: Significant trailing newlines were being stripped. (This code will be pull-requested back to jsHtmlToText at some point.)
31 май 2012, 03:52
31 май 2012, 03:5249c6b61
/*
Copyright (C) 2006 Google Inc.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

HTML decoding functionality provided by: http://code.google.com/p/google-trekker/
*/

/*
adam-p: modified to be a module
*/

;(function() {


function htmlToText(html, extensions) {
    var text = html, i;

    if (extensions && extensions['preprocessing'])
        text = extensions['preprocessing'](text);

    text = text
        // Remove line breaks
        .replace(/(?:\n|\r\n|\r)/ig, " ")
        // Remove content in script tags.
        .replace(/<\s*script[^>]*>[\s\S]*?<\/script>/mig, "")
        // Remove content in style tags.
        .replace(/<\s*style[^>]*>[\s\S]*?<\/style>/mig, "")
        // Remove content in comments.
        .replace(/<!--.*?-->/mig, "")
        // Remove !DOCTYPE
        .replace(/<!DOCTYPE.*?>/ig, "");

    /* I scanned http://en.wikipedia.org/wiki/HTML_element for all html tags.
    I put those tags that should affect plain text formatting in two categories:
    those that should be replaced with two newlines and those that should be
    replaced with one newline. */

    if (extensions && extensions['tagreplacement'])
        text = extensions['tagreplacement'](text);

    var doubleNewlineTags = ['p', 'h[1-6]', 'dl', 'dt', 'dd', 'ol', 'ul',
        'dir', 'address', 'blockquote', 'center', 'div', 'hr', 'pre', 'form',
        'textarea', 'table'];

    var singleNewlineTags = ['li', 'del', 'ins', 'fieldset', 'legend',
        'tr', 'th', 'caption', 'thead', 'tbody', 'tfoot'];

    for (i = 0; i < doubleNewlineTags.length; i++) {
        var r = RegExp('</?\\s*' + doubleNewlineTags[i] + '[^>]*>', 'ig');
        text = text.replace(r, '\n\n');
    }

    for (i = 0; i < singleNewlineTags.length; i++) {
        var r = RegExp('<\\s*' + singleNewlineTags[i] + '[^>]*>', 'ig');
        text = text.replace(r, '\n');
    }

    // Replace <br> and <br/> with a single newline
    text = text.replace(/<\s*br[^>]*\/?\s*>/ig, '\n');

    text = text
        // Remove all remaining tags.
        .replace(/(<([^>]+)>)/ig,"")
        // Make sure there are never more than two
        // consecutive linebreaks.
        .replace(/\n{2,}/g,"\n\n")
        // Remove newlines at the beginning of the text.
        .replace(/^\n+/,"")
        // Remove newlines at the end of the text.
        .replace(/\n+$/,"")
        // Decode HTML entities.
        .replace(/&([^;]+);/g, decodeHtmlEntity);

    /* adam-p: make trailing whitespace stripping optional */

    if (!extensions || !extensions['allowTrailingWhitespace']) {
      text = text
          // Trim rightmost whitespaces for all lines
          .replace(/([^\n\S]+)\n/g,"\n")
          .replace(/([^\n\S]+)$/,"");
    }

    if (extensions && extensions['postprocessing'])
        text = extensions['postprocessing'](text);

    return text;
}

function decodeHtmlEntity(m, n) {
	// Determine the character code of the entity. Range is 0 to 65535
	// (characters in JavaScript are Unicode, and entities can represent
	// Unicode characters).
	var code;

	// Try to parse as numeric entity. This is done before named entities for
	// speed because associative array lookup in many JavaScript implementations
	// is a linear search.
	if (n.substr(0, 1) == '#') {
		// Try to parse as numeric entity
		if (n.substr(1, 1) == 'x') {
			// Try to parse as hexadecimal
			code = parseInt(n.substr(2), 16);
		} else {
			// Try to parse as decimal
			code = parseInt(n.substr(1), 10);
		}
	} else {
		// Try to parse as named entity
		code = ENTITIES_MAP[n];
	}

	// If still nothing, pass entity through
	return (code === undefined || code === NaN) ?
		'&' + n + ';' : String.fromCharCode(code);
}

var ENTITIES_MAP = {
  'nbsp' : 160,
  'iexcl' : 161,
  'cent' : 162,
  'pound' : 163,
  'curren' : 164,
  'yen' : 165,
  'brvbar' : 166,
  'sect' : 167,
  'uml' : 168,
  'copy' : 169,
  'ordf' : 170,
  'laquo' : 171,
  'not' : 172,
  'shy' : 173,
  'reg' : 174,
  'macr' : 175,
  'deg' : 176,
  'plusmn' : 177,
  'sup2' : 178,
  'sup3' : 179,
  'acute' : 180,
  'micro' : 181,
  'para' : 182,
  'middot' : 183,
  'cedil' : 184,
  'sup1' : 185,
  'ordm' : 186,
  'raquo' : 187,
  'frac14' : 188,
  'frac12' : 189,
  'frac34' : 190,
  'iquest' : 191,
  'Agrave' : 192,
  'Aacute' : 193,
  'Acirc' : 194,
  'Atilde' : 195,
  'Auml' : 196,
  'Aring' : 197,
  'AElig' : 198,
  'Ccedil' : 199,
  'Egrave' : 200,
  'Eacute' : 201,
  'Ecirc' : 202,
  'Euml' : 203,
  'Igrave' : 204,
  'Iacute' : 205,
  'Icirc' : 206,
  'Iuml' : 207,
  'ETH' : 208,
  'Ntilde' : 209,
  'Ograve' : 210,
  'Oacute' : 211,
  'Ocirc' : 212,
  'Otilde' : 213,
  'Ouml' : 214,
  'times' : 215,
  'Oslash' : 216,
  'Ugrave' : 217,
  'Uacute' : 218,
  'Ucirc' : 219,
  'Uuml' : 220,
  'Yacute' : 221,
  'THORN' : 222,
  'szlig' : 223,
  'agrave' : 224,
  'aacute' : 225,
  'acirc' : 226,
  'atilde' : 227,
  'auml' : 228,
  'aring' : 229,
  'aelig' : 230,
  'ccedil' : 231,
  'egrave' : 232,
  'eacute' : 233,
  'ecirc' : 234,
  'euml' : 235,
  'igrave' : 236,
  'iacute' : 237,
  'icirc' : 238,
  'iuml' : 239,
  'eth' : 240,
  'ntilde' : 241,
  'ograve' : 242,
  'oacute' : 243,
  'ocirc' : 244,
  'otilde' : 245,
  'ouml' : 246,
  'divide' : 247,
  'oslash' : 248,
  'ugrave' : 249,
  'uacute' : 250,
  'ucirc' : 251,
  'uuml' : 252,
  'yacute' : 253,
  'thorn' : 254,
  'yuml' : 255,
  'quot' : 34,
  'amp' : 38,
  'lt' : 60,
  'gt' : 62,
  'OElig' : 338,
  'oelig' : 339,
  'Scaron' : 352,
  'scaron' : 353,
  'Yuml' : 376,
  'circ' : 710,
  'tilde' : 732,
  'ensp' : 8194,
  'emsp' : 8195,
  'thinsp' : 8201,
  'zwnj' : 8204,
  'zwj' : 8205,
  'lrm' : 8206,
  'rlm' : 8207,
  'ndash' : 8211,
  'mdash' : 8212,
  'lsquo' : 8216,
  'rsquo' : 8217,
  'sbquo' : 8218,
  'ldquo' : 8220,
  'rdquo' : 8221,
  'bdquo' : 8222,
  'dagger' : 8224,
  'Dagger' : 8225,
  'permil' : 8240,
  'lsaquo' : 8249,
  'rsaquo' : 8250,
  'euro' : 8364
};

var EXPORTED_SYMBOLS = ['htmlToText'];

if (typeof module !== 'undefined') {
  module.exports = htmlToText;
} else {
  this.htmlToText = htmlToText;
  this.EXPORTED_SYMBOLS = EXPORTED_SYMBOLS;
}

}).call(function() {
  return this || (typeof window !== 'undefined' ? window : global);
}());