function isString(value) {
      return typeof value == 'string' ||
        value && typeof value == 'object' && toString.call(value) == stringClass || false;
    }
Checks if `value` is a string.

@static
@memberOf _
@category Objects
@param {*} value The value to check.
@returns {boolean} Returns `true` if the `value` is a string, else `false`.
@example

_.isString('fred');
// => true