Function truncate

test-app/public/sinon.js:25695–25749

* Truncates `string` if it's longer than the given maximum string length. * The last characters of the truncated string are replaced with the omission * string which defaults to "...". * * @static * @memberOf _ * @since 4.0.0 * @category

(string, options)

         * // => 'hi-diddly-ho there, neig [...]'
         */
        function truncate(string, options) {
          var length = DEFAULT_TRUNC_LENGTH,
              omission = DEFAULT_TRUNC_OMISSION;
    
          if (isObject(options)) {
            var separator = 'separator' in options ? options.separator : separator;
            length = 'length' in options ? toInteger(options.length) : length;
            omission = 'omission' in options ? baseToString(options.omission) : omission;
          }
          string = toString(string);
    
          var strLength = string.length;
          if (hasUnicode(string)) {
            var strSymbols = stringToArray(string);
            strLength = strSymbols.length;
          }
          if (length >= strLength) {
            return string;
          }
          var end = length - stringSize(omission);
          if (end < 1) {
            return omission;
          }
          var result = strSymbols
            ? castSlice(strSymbols, 0, end).join('')
            : string.slice(0, end);
    
          if (separator === undefined) {
            return result + omission;
          }
          if (strSymbols) {
            end += (result.length - end);
          }
          if (isRegExp(separator)) {
            if (string.slice(end).search(separator)) {
              var match,
                  substring = result;
    
              if (!separator.global) {
                separator = RegExp(separator.source, toString(reFlags.exec(separator)) + 'g');
              }
              separator.lastIndex = 0;
              while ((match = separator.exec(substring))) {
                var newEnd = match.index;
              }
              result = result.slice(0, newEnd === undefined ? end : newEnd);
            }
          } else if (string.indexOf(baseToString(separator), end) != end) {
            var index = result.lastIndexOf(separator);
            if (index > -1) {
              result = result.slice(0, index);
            }
          }
          return result + omission;
        }
    
        /**
         * The inverse of `_.escape`; this method converts the HTML entities