'use strict'; var strValue = String.prototype.valueOf; var tryStringObject = function tryStringObject(value) { try { strValue.call(value); return true; } catch (e) { return false; } }; var toStr = Object.prototype.toString; var strClass = '[object String]'; var hasToStringTag = typeof Symbol === 'function' && !!Symbol.toStringTag; module.exports = function isString(value) { if (typeof value === 'string') { return true; } if (typeof value !== 'object') { return false; } return hasToStringTag ? tryStringObject(value) : toStr.call(value) === strClass; };