Function parsePatternAttr

test/angular/1.7/angular.js:36247–36261

(regex, patternExp, elm)

function parsePatternAttr(regex, patternExp, elm) {
  if (!regex) return undefined;

  if (isString(regex)) {
    regex = new RegExp('^' + regex + '$');
  }

  if (!regex.test) {
    throw minErr('ngPattern')('noregexp',
      'Expected {0} to be a RegExp but was {1}. Element: {2}', patternExp,
      regex, startingTag(elm));
  }

  return regex;
}

function parseLength(val) {
  var intVal = toInt(val);