prototype/src/lang/string.js

Object.extend(String, {
  interpret: function(value) {
    return value == null ? '' : String(value);
  },
  specialChar: {
    '\b': '\\b',
    '\t': '\\t',
    '\n': '\\n',
    '\f': '\\f',
    '\r': '\\r',
    '\\': '\\\\'
  }
});

Object.extend(String.prototype, (function() {
  
  function prepareReplacement(replacement) {
    if (Object.isFunction(replacement)) return replacement;
    var template = new Template(replacement);
    return function(match) { return template.evaluate(match) };
  }
  
  function gsub(pattern, replacement) {
    var result = '', source = this, match;
    replacement = prepareReplacement(replacement);

    while (source.length > 0) {
      if (match = source.match(pattern)) {
        result += source.slice(0, match.index);
        result += String.interpret(replacement(match));
        source  = source.slice(match.index + match[0].length);
      } else {
        result += source, source = '';
      }
    }
    return result;
  }

  function sub(pattern, replacement, count) {
    replacement = prepareReplacement(replacement);
    count = Object.isUndefined(count) ? 1 : count;

    return this.gsub(pattern, function(match) {
      if (--count < 0) return match[0];
      return replacement(match);
    });
  }

  function scan(pattern, iterator) {
    this.gsub(pattern, iterator);
    return String(this);
  }

  function truncate(length, truncation) {
    length = length || 30;
    truncation = Object.isUndefined(truncation) ? '...' : truncation;
    return this.length > length ? 
      this.slice(0, length - truncation.length) + truncation : String(this);
  }

  function strip() {
    return this.replace(/^\s+/, '').replace(/\s+$/, '');
  }

  function stripTags() {
    return this.replace(/<\/?[^>]+>/gi, '');
  }

  function stripScripts() {
    return this.replace(new RegExp(Prototype.ScriptFragment, 'img'), '');
  }

  function extractScripts() {
    var matchAll = new RegExp(Prototype.ScriptFragment, 'img');
    var matchOne = new RegExp(Prototype.ScriptFragment, 'im');
    return (this.match(matchAll) || []).map(function(scriptTag) {
      return (scriptTag.match(matchOne) || ['', ''])[1];
    });
  }

  function evalScripts() {
    return this.extractScripts().map(function(script) { return eval(script) });
  }

  function escapeHTML() {
    escapeHTML.text.data = this;
    return escapeHTML.div.innerHTML;
  }

  function unescapeHTML() {
    var div = new Element('div');
    div.innerHTML = this.stripTags();
    return div.childNodes[0] ? (div.childNodes.length > 1 ? 
      $A(div.childNodes).inject('', function(memo, node) { return memo+node.nodeValue }) : 
      div.childNodes[0].nodeValue) : '';
  }

  function toQueryParams(separator) {
    var match = this.strip().match(/([^?#]*)(#.*)?$/);
    if (!match) return { };

    return match[1].split(separator || '&').inject({ }, function(hash, pair) {
      if ((pair = pair.split('='))[0]) {
        var key = decodeURIComponent(pair.shift());
        var value = pair.length > 1 ? pair.join('=') : pair[0];
        if (value != undefined) value = decodeURIComponent(value);

        if (key in hash) {
          if (!Object.isArray(hash[key])) hash[key] = [hash[key]];
          hash[key].push(value);
        }
        else hash[key] = value;
      }
      return hash;
    });
  }

  function toArray() {
    return this.split('');
  }

  function succ() {
    return this.slice(0, this.length - 1) +
      String.fromCharCode(this.charCodeAt(this.length - 1) + 1);
  }

  function times(count) {
    return count < 1 ? '' : new Array(count + 1).join(this);
  }

  function camelize() {
    var parts = this.split('-'), len = parts.length;
    if (len == 1) return parts[0];

    var camelized = this.charAt(0) == '-' 
      ? parts[0].charAt(0).toUpperCase() + parts[0].substring(1)
      : parts[0];

    for (var i = 1; i < len; i++)
      camelized += parts[i].charAt(0).toUpperCase() + parts[i].substring(1);

    return camelized;
  }

  function capitalize() {
    return this.charAt(0).toUpperCase() + this.substring(1).toLowerCase();
  }

  function underscore() {
    return this.gsub(/::/, '/').gsub(/([A-Z]+)([A-Z][a-z])/,'#{1}_#{2}').gsub(/([a-z\d])([A-Z])/,'#{1}_#{2}').gsub(/-/,'_').toLowerCase();
  }

  function dasherize() {
    return this.gsub(/_/,'-');
  }

  function inspect(useDoubleQuotes) {
    var escapedString = this.gsub(/[\x00-\x1f\\]/, function(match) {
      var character = String.specialChar[match[0]];
      return character ? character : '\\u00' + match[0].charCodeAt().toPaddedString(2, 16);
    });
    if (useDoubleQuotes) return '"' + escapedString.replace(/"/g, '\\"') + '"';
    return "'" + escapedString.replace(/'/g, '\\\'') + "'";
  }

  function toJSON() {
    return this.inspect(true);
  }

  function unfilterJSON(filter) {
    return this.sub(filter || Prototype.JSONFilter, '#{1}');
  }

  function isJSON() {
    var str = this;
    if (str.blank()) return false;
    str = this.replace(/\\./g, '@').replace(/"[^"\\\n\r]*"/g, '');
    return (/^[,:{}\[\]0-9.\-+Eaeflnr-u \n\r\t]*$/).test(str);
  }

  function evalJSON(sanitize) {
    var json = this.unfilterJSON();
    try {
      if (!sanitize || json.isJSON()) return eval('(' + json + ')');
    } catch (e) { }
    throw new SyntaxError('Badly formed JSON string: ' + this.inspect());
  }

  function include(pattern) {
    return this.indexOf(pattern) > -1;
  }

  function startsWith(pattern) {
    return this.indexOf(pattern) === 0;
  }

  function endsWith(pattern) {
    var d = this.length - pattern.length;
    return d >= 0 && this.lastIndexOf(pattern) === d;
  }

  function empty() {
    return this == '';
  }

  function blank() {
    return /^\s*$/.test(this);
  }

  function interpolate(object, pattern) {
    return new Template(this, pattern).evaluate(object);
  }
  
  return {
    gsub:           gsub,
    sub:            sub,
    scan:           scan,
    truncate:       truncate,
    strip:          strip,
    stripTags:      stripTags,
    stripScripts:   stripScripts,
    extractScripts: extractScripts,
    evalScripts:    evalScripts,
    escapeHTML:     escapeHTML,
    unescapeHTML:   unescapeHTML,
    toQueryParams:  toQueryParams,
    parseQuery:     toQueryParams,
    toArray:        toArray,
    succ:           succ,
    times:          times,
    camelize:       camelize,
    capitalize:     capitalize,
    underscore:     underscore,
    dasherize:      dasherize,
    inspect:        inspect,
    toJSON:         toJSON,
    unfilterJSON:   unfilterJSON,
    isJSON:         isJSON,
    evalJSON:       evalJSON,
    include:        include,
    startsWith:     startsWith,
    endsWith:       endsWith,
    empty:          empty,
    blank:          blank,
    interpolate:    interpolate
  };
})());

if (Prototype.Browser.WebKit || Prototype.Browser.IE) Object.extend(String.prototype, {
  escapeHTML: function() {
    return this.replace(/&/g,'&amp;').replace(/</g,'&lt;').replace(/>/g,'&gt;');
  },
  unescapeHTML: function() {
    return this.stripTags().replace(/&amp;/g,'&').replace(/&lt;/g,'<').replace(/&gt;/g,'>');
  }
});

Object.extend(String.prototype.escapeHTML, {
  div:  document.createElement('div'),
  text: document.createTextNode('')
});

String.prototype.escapeHTML.div.appendChild(String.prototype.escapeHTML.text);