Rule for validating minimum and maximum allowed values.

@param rule The validation rule.
@param value The value of the field on the source object.
@param source The source object being validated.
@param errors An array of errors that this rule may add
validation errors to.
@param options The validation options.
@param options.messages The validation messages.
function range(rule, value, source, errors, options) {
  const len = typeof rule.len === 'number';
  const min = typeof rule.min === 'number';
  const max = typeof rule.max === 'number';
  // 正则匹配码点范围从U+010000一直到U+10FFFF的文字（补充平面Supplementary Plane）
  const spRegexp = /[\uD800-\uDBFF][\uDC00-\uDFFF]/g;
  let val = value;
  let key = null;
  const num = typeof (value) === 'number';
  const str = typeof (value) === 'string';
  const arr = Array.isArray(value);
  if (num) {
    key = 'number';
  } else if (str) {
    key = 'string';
  } else if (arr) {
    key = 'array';
  }
  // if the value is not of a supported type for range validation
  // the validation rule rule should use the
  // type property to also test for a particular type
  if (!key) {
    return false;
  }
  if (arr) {
    val = value.length;
  }
  if (str) {
    // 处理码点大于U+010000的文字length属性不准确的bug，如"𠮷𠮷𠮷".lenght !== 3
    val = value.replace(spRegexp, '_').length;
  }
  if (len) {
    if (val !== rule.len) {
      errors.push(util.format(options.messages[key].len, rule.fullField, rule.len));
    }
  } else if (min && !max && val < rule.min) {
    errors.push(util.format(options.messages[key].min, rule.fullField, rule.min));
  } else if (max && !min && val > rule.max) {
    errors.push(util.format(options.messages[key].max, rule.fullField, rule.max));
  } else if (min && max && (val < rule.min || val > rule.max)) {
    errors.push(util.format(options.messages[key].range,
      rule.fullField, rule.min, rule.max));
  }
}